Huh? Which rule is that?
Why would explaining why he thinks they're Sony biased be against the rules while just saying that they are...isn't?
Usually if you say something controversial or "out there", it's better to actually explain. Otherwise it could be misunderstood.
I'm not sure it's black on white in the rules, but from one of tads' latest announcement threads there was mention of keeping mod criticism out of threads that weren't marked for that (monthly ban thread and other threads made for that).
So, asking him to give proof as to why one mod may be Sony biased could get him banned pretty much.
If you weren't aware then that's ok.