The problem is that many online communities foster this sort of thing and allow it to fester and grow..as if it's perfectly acceptable.
Reddit has subreddits that I've seen that are dedicated to this behavior and sites like Twitter and Facebook will only get rid of posts if it fits the current political narrative. I've seen republicans/conservatives get death threats against their kids with no bannings, but if you misgender someone, it's an instant ban.
Its these sorts of double standards that allows hate to flourish and sends a signal to the person doing it that it's acceptable behavior, so it not only continues, but gets worse...and the person sending the hateful messages will never stop there.