I can and have removed both comments and posts from lemmy.world due to reports made here. I banned a user from this instance, not lemmy but I don’t know how it handles bans from other instances and I would like to keep it that way. I receive reports about other instances from users made in this one, not from other instances about this one or other instances about other instances.

Edit: Just confirmed that a post I removed from lemmy.ml is removed for myself while logged out and in another browser, so I am able to remove posts elsewhere. This is a personal fear of mine, as an admin with less than reputable honor could decide one day that they don’t like the word ‘birthday’ for instance and remove anything with that word in it. I understand the idea behind it but humanity has shown that it cannot be responsible enough when granted power.

It is an intended feature per request.