I guess it prevents them from participating in the replies to your tweets, so it prevents your access to the parent’s audience. A tweet is kind of like a stage,

I guess it prevents them from participating in the replies to your tweets, so it prevents your access to the parent’s audience. A tweet is kind of like a stage, you might have a million followers, everyone who replies is also seen by your audience. Blocking is like preventing people from getting up on your stage.