Sadly we're at a point where you get in trouble for using racial slurs but not for using the word my old friend. In my opinion, if you get in trouble for using racist words, then you should get in trouble for using that word also. Some admins use it too. CHAOS loves that word
The term my old friend is such a broad term and has several different meanings and feelings behind it, while most racial epithets do not. And steve hughes said it best, it really is subjective.
And there is no such thing as free speech on a gaming server, the owner of it has every right to regulate it in whatever way he wishes. If chadz wants to ban people for saying "pudding", there is nothing stopping him.
With that said, there is nothing stopping you from boycotting the server and seeking out other pudding-friendly alternatives.