Life is very simple. It's always the person who retaliates that gets caught\punished.
Fans and spectators have nothing to lose. Their public image means nothing, they are not on someone's payroll, they don't represent someone's brand, nor do their actions directly effect their marketability.
A spectator can say and do anything, but if an athlete my company sponsors, or my broadcast is associated with, or my tournament is allowing to play, says that same thing, it's NIGHT and DAY difference. Her actions do not reflect on anyone other than herself, and likely her husband.
Pete's action directly reflect on the tournament, the PBA, Storm, and probably 5 other companies that compensate him to use their products.
It's not that complicated. A spectator can be a POS human and get away with it, but an athlete can not. Not if you want people to pay to be associated with you.
Anyone who's ever watched any other sport in the world knows exactly how this works. Pete should consider himself lucky that no one cares about bowling like they do bigger sports, otherwise every sports network would be blasting him for the way he treated that "poor woman" even if she started it\deserved it, that's the narrative that would be on headlines. "60 year old bowler makes obscene gesture to female spectator, implying to 'suck his ****'." Then the court of public opinion trickles into your wallet, companies get pressured to drop you, cut ties, etc etc etc.
Imagine if an NFL or NBA player did this to a spectator, we wouldn't hear the end of it for weeks, they'd get suspended multiple weeks for conduct detrimental to the league, be forced to make an apology, the team would have to make a statement condemning his actions, yadda yadda. Combine that with what he tweeted after... Yikes.
He got off easy in the grand scheme.