Communities have given death threats to college students who made bad plays in sports games. https://abcnews.go.com/Sports/ncaa-1-3-star-athletes-receive...
There's a long-established pattern linking bullying and suicide, and huge amounts of tougher-to-quantify lesser damage done. Giving people mechanisms to slow and reduce bullying makes perfect sense.
Not saying the people making death threats are innocent and of course the law should try to stop them, but often it's not powerful enough so people who don't want that unfortunately have to keep quiet or be anonymous when they want to step on the toes of death-threat-happy communities.
Again, it's not just bullying. Real world example:
* The quarterback (QB) for Miskatonic University throws an interception on the last play of the game.
* Internet members (trolls) find their Twitter handle. Trolls harass QB, insult QB, and make QB's lives miserable. They publish QB's handle on their forums where other trolls also harass QB.
* QB blocks the trolls
Which scenario is better for QB, non-trolling users, advertisers, and the world?
1. The trolls still see can follow QB and respond to everything they do. Maybe QB can't see their messages, but the trolls are free to harass QB's followers, the staff of any location QB posts to being at, and so on. They continue harassing over and over. For years and years they can see QB's posts and continue engaging.
2. The trolls cannot see QB's posts, follower lists, or engage with them. A few particularly dedicated trolls may use alt accounts but it's a tiny percentage of the original trolling and much easier to manage. They eventually get distracted with some other player who made a newer mistake and leave QB alone.
I've heard celebrities say they don't read what anyone says about them on social media. That sounds like a good idea because there's always going to be haters to any popular public figure. Just ignore them and you're fine.
3rd parties being affected? Well stop associating with the widely-hated public figre if you can't handle the heat of celebrities.
What if you're a holocaust denier? What are you going to do? Somehow not share your belief with the world? Yes! Either that or accept the hateful responses you're bound to get if you do share it.
Don't forget this is all about public posts. Not anyone's private life or stuff they only share with people they trust. There's always going to be a Muslim somewhere who wants to kill you for being a practicing gay, or a holocaust believer who wants to punish you for disagreeing with their it-did-happen belief.
What about an ashiest who ties their belief to rejecting the identities of Christians? There's no end to what people vehemently disagree on.
By the way, you can always change your identity if you really want to. Just because you're gay doesn't mean that has to be your identity. You might primarily see yourself as a citizen of your country or what your job defines you as or your personality or religion or just simply yourself if you don't want to be part of a bigger group.
Society does not have to just let the worst people in it be as they are. Neither do platforms. Bullying and hateful abuse hurt the platform - users don't want to be subjected to it, advertisers don't want their name next to it. Blocking and other tools to reduce this vile garbage are positive things.