It's stupid really. You are taking the choice out of person's hands. So what, I am supposed to automatically broadcast everything I post in other communities, all the music I listen to, the streams I am watching? Have a share button... sure, but not automatically broadcast it.

I can't control what a client displays, but I don't want to see random non-community replies in my community. Nor would I want to spam my followers with content not intended for them because they don't share those interests.