Piker has been preaching violence for years, and none of his followers batted an eye.
It wasn't until he used a shock collar to punish his dog for stepping off the bed she's forced to lay on on for 4+ hours at a time, that his audience is waking up to what a piece of shit he is.
Some part of that backlash could very well be stoked by ulterior motives, sure. This is an information war, and there a lot of powerful interests that want to see Piker's influence continue to grow.