She's just another old-school mother who can't wrap her mind around modern society as far as I'm concerned.
It's too simplistic to just peg her as a dumb Christian, a notion that I honestly think society would be better off purging altogether; that is the labeling others based on the groups they're a part of rather than as individuals. We should treat others equally, not as part of some kind of assumed insane hive mind. Worse than that is assuming these groups are trying to pee in the pool and ruin it for everyone; like their elite gather in underground bunkers with lots of TVs on the wall and scheme and cackle madly, stroking their handlebar mustaches.
That said, this mother is clearly ignorant to the world around her and the guy who deleted her post was right to do so, though I kind of wished he had engaged in an intelligent discussion with her rather than just flat-out deleting her post. It doesn't help the problem to ignore it.