It's kinda like if there was a magic bulletin board that everyone has in their home.

When someone adds something to the board, everyone else can see it on theirs.

If you don't like what someone is posting on their board, you can choose to stop seeing those messages.

No one can tell you what to post on the board, or what not to. No one owns the network of bulletin boards, it's kind of similar to public infrastructure, like a sidewalk or a road.