well, too be fair, his only crime was not passing on. Even as he started to turn, he did his best to not latch out, so his sentence is significantly lighter then the others. He merely has to climb a ladder to heaven as penance
Buddha is Buddha, the greatest delinquent the world's ever seen. No one can make him do anything, he comes and goes as he pleases, but he also wants to help people, that's how he became a god in the first place. This whole Ragnarok business probably irks him greatly.