I think part of the reason for this is that you have a lot of these dipshit parents who see headlines like this and think "the LiBeRaLs are going to use this week's school shooting as justification for taking our guns; I'll show them, I'll give my children guns and be the proof that guns aren't the problem". At least, with how often I see the sentiment of "well my kids have guns and haven't killed anybody" across social media, that's my assumption.
They all think they're responsible gun owners. And maybe some of them are. Hell, maybe most of them are. But a non-zero amount aren't, and we need to have safeguards in place instead of "nothing we can do but pray for stronger doors on the schools".