The fanbase is so violent toward haters because they're a bunch of hormonal teenage girls or those of an equivalent mental maturity. They respond violently to a lot of things they don't like.

The lead singer dude is called a pedophile because of numerous accusations of him engaging in sexual activity with minors. Also a couple accusations of rape.

My opinion is that they produce the musical equivalent of vomit and the people who make up the band are awful. One of just many incidents of them being awful includes one of the dudes on Twitter making rape jokes after the whole rape accusation thing. They're garbage, both musically and as people.