Female and male rectums are biologically and physically the same. There is no difference.
If you would have a shaved anus behind a gloryhole and put your dick inside it you would feel no difference if it would be a man or a woman. Absolutely zero difference and zero biological purpose. While intercourse with a vagina feels different and has a higher biological purpose of proliferation.
So why would you even have anal sex with women if it feels same as anal sex with men? It's gay.
Conclusion: The anal porn genre may have been one of the biggest psy ops to normalize or even idealize gay sex.