Sins of the Fathers

Ezekiel 18:20 “The soul who sins is the one who will die. The son will not share the guilt of the father, nor will the father share the guilt of the son.”

Apparently the radical right - which is the dominant conservative majority for the moment, in the era of Donald Trump, has gone off their nut over the appearance of the Muslim father of the Muslim Orlando mass shooter at a Hillary campaign appearance (as distinct from the other mass shooters in Florida during the same time frame).But focusing on this is preferable to conservatives to the latest Trump scandal.
Mir Seddique Mateen showed up in a crowd and was recognized. So what? There is no reason to deny him participation in our election process. That would be unconstitutional, since that document forbids any test of religion for office and by extension for participating in elections.
You can't prevent someone from voting for example just because you don't like their religion. But that wasn't enough; the right has sought to smear this man by making false claims, in the hopes by extension not only to damage Mateen but also Hillary Clinton. Clinton's campaign noted they did not know he was present, did not invite him. As noted by Politico:

Clinton kicked off her Florida rally by talking about the massacre, offering condolences to those still grieving and pledging to “be with you as you rebuild your lives.” ...Seddique Mateen told the reporter that he is a Clinton supporter and even held up a sign he had made touting her as “good for national security” as well as her call for more aggressive gun control laws. “Clinton is good for United States versus Donald Trump,” he said. The father said he had been invited to the event as a Clinton supporter but had not received any special invitation from the campaign. The rally was open to the public and the Clinton campaign told WPTV that it did not know that Seddique Mateen was at the event until it had ended. "The rally was a 3,000-person, open-door event for the public,” a Clinton campaign official told the station. “This individual wasn't invited as a guest and the campaign was unaware of his attendance until after the event."
...
Asked by the WPTV reporter if he thought the public would be surprised to see him at a public event so close to Orlando, the gunman’s father responded that he was puzzled by the question’s premise.
“Why they should be surprised?” He said. “I love United States and I’ve been living here for a long time.”

That part Politico got right. What Politico did NOT get right was this, apparently repeating a story from CBS without fact checking it:

While he appeared patriotic at Monday’s rally, Seddique Mateen has a history of offering pro-Taliban and anti-U.S. rhetoric on his satellite TV program, which is based in the U.S. but geared toward Pashtun Afghans living in America and Europe.

In fact, quite the opposite, Mateen senior was strongly anti-Taliban and anti-Pakistani intelligence associated with hiding bin Laden. In fact it makes sense that Mateen would be pro-Hillary, given she was part of the administration and specifically in the situation room when bin Laden was attacked and killed by US special forces. From Reuters:

Khatab said Seddique Mateen's political views were largely anti-Pakistan. A YouTube channel under Mateen's name had more than 100 videos posted between 2012 and 2015. One of the videos refers to the "killer ISI" - the acronym for Pakistan's main military-run intelligence service - and says the agency is the "creator and father of the world's terrorism." U.S. officials have accused Pakistani intelligence of backing violence against U.S. targets in Afghanistan, although Pakistan denies the allegations. n a February video on his Facebook page, he addresses Taliban members and castigates them for being the "servants" of the ISI. In a June 11 video posted on Facebook, Mateen is dressed in military fatigues and says Afghanistan must "punish the traitors."

This was confirmed as well by the Florida Palm Beach Post interview:

“He’s obviously against Taliban and ISIS and all that,” said Qasim Tarin, a fellow Afghan expatriate who appeared on Seddique Mateen’s YouTube show and followed him on Facebook.
“I’ve known him for a long time. To his Facebook and all, he is absolutely against ISIS and Pakistanis and, of course, ISI intelligence,” the Pakistani security agency some suspect of involvement in terrorism.

Mir Siddique Mateen is apparently in denial about his son's sexual orientation, which follows a pattern of denial that was observed when the shooter, Omar Mateen, was a child.  But equally, his father  and brother in law no longer claim that homosexuality was the cause of the shooting.  Further while Mir Siddique Mateen is far from enlightened as regards LGBT sexuality, he does himself leave it to God to address rather than humans.  So the man's a homophobe, but not one of the more virulent who wants them discriminated against in some way.  Nor did he attend a radical mosque as the far right wing rags falsely reported, pandering to ginning up Islamophobia  .
So..........why shouldn't he go to a Clinton event?  The father of the shooter did nothing wrong, and appears to have been unaware of what his son, who lived separately, did. As ABC noted:

Though on television it appeared that Mateen was close to Clinton, he was well outside of the security buffer zone in a location that a longtime Republican presidential campaign advance staffer described as a "tapestry" -- an area where a diverse group would be seated to reflect wide-ranging support for the candidate.