What DOES the Confederate Flag Represent to Southerners?

Confederate bigot flag loving, cross burning KKK

Many of us wonder why the heck Southern racists keep yammering on and on about how the Confederate flag is a symbol they honor, heritage, blah blah blah blah blah.
Here is one example of a comment on a FB page, in response to a prior comment that the Confederate secession was treason, about the news a county in Florida had taken down the Confederate flag and then put it back up again:

Treason? There was nothing treasonous in the South reclaiming their State soveriegnty. In fact, they were following the spirit of the Declaration of Independence in doing so, but I guess a hardcore, treasonous liberal can't understand that.

Based on the inability of the commenter to spell properly, I'm betting this is from another teabagger style conservative. (Sovereignty, it is not soveriegnty.)
Anyone, including am liberal with an adequate history and civics education, knows that the secession by violence of the southern states, including Florida WAS TREASON, as defined in the U.S. Constitution, specifically Article III, section 3:

Treason against the United States, shall consist only in levying War against them, or in adhering to their Enemies, giving them Aid and Comfort. No Person shall be convicted of Treason unless on the Testimony of two Witnesses to the same overt Act, or on Confession in open Court.
The Congress shall have Power to declare the Punishment of Treason, but no Attainder of Treason shall work Corruption of Blood, or Forfeiture except during the Life of the Person attainted.

This article and section exists because of the earlier experience of the United States under the Articles of Confederation and Perpetual Unity, where there were both small rebellions like Shay's Rebellion (1786-7) and individual wars between states like the Yankee Pennamite war (1769 - 1791).  To expand on what is included and what was rejected in defining treason in the U.S. Constitution  (1787), from wikipedia:

Under English law effective during the ratification of the U.S. Constitution, there were essentially five species of treason. Of the five, the Constitution adopted only two: levying war and adhering to enemies.

Proper legal secession is the reverse of joining the Union; it requires a similar vote of the states to allow a state to seceded, the mirror of accepting a state joining the Union.  It is peaceful, and it requires a broader consensus than just what any one states wants at some point in time.  This is because the founders understood from their experience under the comparatively libertarian Articles of Confederation and Perpetual Unity that a strong federal government was essential.  That experience is the reason the Articles of Confederation were replaced by the U.S. Constitution.
Therefore it was no surprise or secret, no surprise to those southern states that waging war against the Union they joined with their eyes wide open -- and in some cases like Virginia, Georgia, and the Carolinas participated in from the beginning -- that waging war was treason, not legitimate secession, and certainly not consistent with or like the conflict with the UK of the American Revolution.
Here is the applicable wording of the Declaration of Independence, with(which the pro-Confederate commenter appears unfamiliar.  You can view the entire text of the Declaration of Independence here for the complete list of wrongs against the colonies, but I think it is a fair observation that it is something of a 'kitchen sink' list, and that not all wrongs or perceived wrongs were equally serious or significant .  Below is the intro to the Declaration of Independence, followed by a few of those more important and substantive issues that distinguish and separate the American Revolution from the Southern War of Aggression (they started it), which was primarily about slavery, both directly and indirectly. 
Nothing could be more ironic and offensive than claiming a war to perpetuate slavery was consistent with all men being created equal, or having unalienable Rights, including Life, Liberty and the pursuit of Happiness -- NONE of which applied to those held in slavery, and which at best minimally applied to the poor white underclass of the Confederacy. 

We hold these truths to be self-evident, that all men are created equal, that they are endowed by their Creator with certain unalienable Rights, that among these are Life, Liberty and the pursuit of Happiness.
That to secure these rights, Governments are instituted among Men, deriving their just powers from the consent of the governed

Here are a few of the wrongs which justified the rebellion of the American colonies, notably the principle complaint was  taxation without representation - NONE of these can fairly be claimed of the United States federal government, where the slave holding states had exactly the representation they had negotiated as a compromise in the U.S. Constitution:

For cutting off our Trade with all parts of the world:
For imposing Taxes on us without our Consent:
For depriving us in many cases, of the benefit of Trial by Jury:
For transporting us beyond Seas to be tried for pretended offences:
For taking away our Charters, abolishing our most valuable Laws and altering fundamentally the Forms of our Governments:
For suspending our own Legislatures, and declaring themselves invested with power to legislate for us in all cases whatsoever.

States rights, and the Confederate flag has always represented one thing and one thing only to the exclusion of all other claims for it -- treason and oppression, violence and brutality of the worst quantity and quality, and conservatives wanting to justify something bad that the federal government prevented them from doing, like Jim Crow.  There has never been any honor or other desirable quality represented by EITHER states rights OR the Confederate flag, LEAST OF ALL all men being created equal, unalienable rights, or life, liberty or the pursuit of happiness.
It is on a par to this country and our heritage and history what the Nazi flag is to the history and heritage of Germany, except that our shameful era lasted longer, and tortured and killed more people, and stole the labor of more human beings.  At least the Nazis never sold anyone.  Only those who posit that African American lives did not matter then when they were slaves and do not matter since the Civil War under Jim Crow can claim that the Confederate flag represents anything else.
It's time for southerners to drop the bogus attitude of being aggrieved, pull up their big boy and big girl britches, and find themselves a new flag or other symbol.  Although since no other regional group of states feels any need to identify in this divisive manner, I don't really see any merit or need for them to bother.  The Confederate flag was for vicious and conservative racists then, and it is the emblem of vicious and conservative racists NOW.
If you believe that the Confederate flag is consistent with the Enlightenment principles of the founding fathers, then you are lying to yourself, and you are in denial of the reality.  That painful reality was yes, a gracious way of life, with gentility and a slow pace --- that existed only by the stolen labor, enforced ignorance, and enslavement of others.  That painful reality is that the life of the white underclass was horrific as well, in part because of the economic consequences of slave labor.  That painful reality was that Confederate flag symbolizes  a  systematic way of life that involved and accepted white men raping black women and then forcing or selling their own illegitimate children into horrific conditions, including expecting their daughters would be raped by future owners as well.  That is not freedom or equality or even basic human decency.   While all of that is sanctioned by the Bible, and by the alternate reality 'Murica', it is not any part of the heritage held dear by those who live in, are loyal to and love the REAL, historically accurate AMERICA under a very different flag.