I've scoured the internet and I can't find the original post stating that the buying and selling of FCs was considered a form of cheating, and thus, not "game legal". Can anyone help me with this?

PS: No, it's not in my history because I was on my phone at the time and it wipes the history daily.

And while we're on the topic, is the buying and selling of boss kills and such actually "game legal"? I know it happens, but is it technically meant to be happening?