Lots of people say dumb things in the heat of the moment. Choosing to stick by it and not apologize is the confirmation dialogue for showing your character.

He afterwards paid someone to dig up more dirt and emailed media with further lies about the guy. At that point it kind of stops being "heat of the moment".

Oh, but it wasn't just that one thing. It's just layer upon layer with that guy. This one was pretty damn bad though

An expert in the field risks their life to save children, is accused of being a peadophile. That's a long way from being an a-hole.

Yeah if every harmful thing constituted the "true character" of someone, we'd all be sinners. Granted, if a lot of harm is done, then it might be fair. (Cue the knee-jerk "isn't dragging a hero's name through the mud a lot of harm?"; I don't know, can you tell me what wouldn't qualify as a "lot of harm" under your worldview? Everyone knows the diver was a hero and if you have evidence his life is affected, pls share)

It's just negativity bias; considering the negative to be "more true" or accurate than the positive.