Puritanical fandom can be blamed for plenty, but I don't think I'd blame it for this. I think, for the most part, there aren't a lot of one night stand fics because that's just not what the majority of fandom wants to read and write, the majority of the time. I mean, it's certainly no secret that shipping is...kind of a huge driving force behind a lot of fandom. And for the most part, one night stands just aren't very shippy. Unless you end the fic with them kind of falling for each other and wanting to see each other again - but then it's not so much a one night stand fic as an alternate meeting hookup fic. *shrugs*

I'm not saying no one has ever been kink shamed for writing a one night stand fic. But I don't think shaming and/or fear of shaming accounts for the lack of such fic.