My mother volunteered at the AIDS service in my hometown. She probably knew more AIDS patients than me. Sometimes I wonder if she chose that role as a way to generate karma for me. I guess it worked.
When I started dating, back then a lot of guys opted to avoid anal. Of course some laughed at that idea. But, as others mentioned above, that was a frightening time.
Also, back then, in my memory, being the "bottom" had a stigma attached. I remember a famous, super masculine porn actor being asked, "why do you bottom?". He said "because it feels good". But many of us weren't taught much, including why anal can feel good.
So with that stigma attached, and the terrible fear of AIDS, avoiding anal made sense. It scared me.
I didn't understand the "feels good" part until later. So, as I mentioned in the prior post, my naivete was in my favor.
My sense today is young men are much more aware of sexuality and their body, and more apt to want to receive anal.