Punk is also the type of guy that won't shoot his mouth off unless he knows he can defend himself in court for it, and win.
He won against WWE's doctor, who was likely money backed in some way by WWE for that trial, and he won the case with Colt Cabana. Despite how the optic is of being a jerk to what was formerly his best friend, Punk isn't one to pick a verbal fight if he doesn't think he can win in the end.
I'd believe anything he said about the Elite was either true, or something he believed to be true, whether it was from a credible source or not. I don't think he should have approached it the way he did, but I understand the desire to set things straight if all that's being told is one lop side of the story.