I’ve been working out regularly for 20+ years in a gym and have never seen it either. If anything, I’ve seen the opposite, the super-fit go out of their way to encourage those who are unfit or just starting because they know the difficulties. I’ve literally never even been given a weird look when asking if I can work in on equipment even with the most intimidating gym rats. And this includes me doing a number of gym faux pas early.
I’m sure legitimate bad experiences do happen, but I also think a lot of perception is based on the stories we make up in our own heads.
Sorry you had foul experiences, but I’ll stick to 2% of the people being in that bucket.