I'm 99% sure that it's not that they didn't care to enforce a penalty there, but that they realised that doing so would sink them even further, given the debacle. Yeah, it's arbitrary, but the alternative would have been even more damaging. The moment another player breaks the ruleset during the height of the controversy, Bizzard was in a catch-22, and no action or inaction there would have been "good". The best they could do was letting it slide, and hope that it wouldn't rile up people further.

Also there is a marked difference between holding a paper sign five seconds after a game, and openly making your statement during a spoken interview.