That is, they want to be able to post things that show vulnerability without having the posts be visible to people who will attack people that show that vulnerability. They want less visibility.

For once somebody like this is expressing themselves in a blog and actually expressing themselves. It still seems to me to be a naive position; there is the fight over blocking in Twitter right now where people are claiming they need blocks so that their enemies can’t read their posts but what stops their enemies from making another account? (I guess the block still stops replies though)

If people are that sensitive however they probably should be in a closed space of some kind.

For example, reading the conversation that follows from a single tweet. There's pages of culture war bullshit, spam, AI, paid blue checks that all gets ranked more highly in the replies than what quality discussion there might be.

Another example, let's say you post a tweet. The tweet is shown to others who aren't following the strict chronological timeline of their own followers. The "algorithm" (whatever that is) shows it to people who hate your stance, because that's what drives engagement/revenue, and now your own replies are flooded with shit.