Are you saying that if Fischer lost to Karpov, you wouldn't think he was a one-hit wonder?
For not going along with the terms of his title defense. If you're saying those terms weren't rejected until 1975, then it would be the reason for him not defending his title but I have a hard time believing Fischer didn't propose his terms and FIDE didn't reject them (formally or informally) until '75.
The OP and others who defend the belief that Fischer was a one-hit wonder are basing that off him winning the WCC only once. So I'm using that standard to evaluate Tal and Petrosian as well.
It's not enough to say Tal and Petrosian aren't one-hit wonders because they continued playing after winning the WCC because if Fischer had done the same and lost the title to Karpov, we'd still hear Fischer bashers saying he was a one-hit wonder
No we wouldnt.
"So maybe Fischer's rationalization was that he was punishing FIDE again by not playing after the 72 WCC. "
Punishing them for what?