My partner claims some men don't clean their ass hole in the shower or even wipe in some cases because "its gay". Is this true?

This is absolutely true. I worked with a dude that we had to fire due to being extremely unhygienic, was asked to do something about literally smelling like shit(We worked in food, he was very, very clearly unhygenic and unsafe around the food) and he threw a fit about how wiping his ass/touching it in the shower would make him gay.

He didn't start like that as far as I know, but after like a year of working there, so I guess he heard from someone that it was the case and took it to heart or had some kind of mental issues around that time? Idk

It's the only guy I've known to do it, so it's not a common thing at all, but they're absolutely out there.