Here's where I think things cross from reasonable into unreasonable:
Those who post content they know some people may not want to see ought to be able to self-censorship such that those who don't want to see their content won't see it, but those who do want to see it will.
Likewise, if someone is not self-censoring, then each individual user ought to be able to opt out of seeing their posts by blocking them.
However, under no circumstances should one user, who did not post the content, be able to affect whether or not other users see that content, unless those users specifically agreed to allow that user to curate what shows up in their feed.