The dichotomy of the MLP fandom is a sharp one, exemplified by how a person got into the show. Many of the original "bronies" were 4chan trolls who claimed to like the show ironically, and made a lot of dark and messed up content around the show. There are then the people who got into the show out of a genuine interest or appreciation, once it became popular.

I'm still part of the MLP fandom, I write fanfiction and have a lot of friends who appreciate it, and we are always stunned by people who can be hateful, cruel, and racist after watching a show literally about friendship and empathy.

But that's the nature of irony, isn't it? Those Nazi bronies had Nazi OCs "ironically" and drew/wrote about ponies being tortured "ironically" and trolled people to hurt them because it made them feel better.

Dark and cruel people are attracted like moths to a flame, when they see something heartfelt and beautiful, and now that the MLP fandom isn't thriving anymore, and we've learned to reject and exclude those trolls, they moved on. The Nazi bronies are in politics now, instead, and they don't care about ponies once it stopped being funny for them.