This has been the case for about six months, we had a lot of problems with spam (not regular users) and this was one way to solve it. Also each ping in a post increases load time (look up the user, if that user exists send them an event, and send it to node to send them a live event, etc) for pushing that post.

Like I've said a bunch in the past, it sucks that we have to limit these kinds of things but its the reality.