Generally speaking, most everybody who plays CF has friends who play CF. This is not a problem. Talking to people about CF, sharing a CF experience with other players is a positive.

The problem in your situation and with several others is this. When you roll characters with the specific intention to only level with each other. You roll a character to complement your friend (shaman + thief w/cheapshot) etc. and you constantly abuse this to gain unfair advantages.

There are specific examples where playing with friends becomes permaing as well, such as trying to stack an imperial council so that player X can become Emperor.

Playing with friends is a part of CF, but abusing that to gain unfair advantages or with intent to solely group etc with specific people is not. It's unfair to other players in all the situations mentioned and that's why you were spoken to.