I think it's a psychoogical thing with some women, if a woman wants to brand you too big or brand herself too tight - she will always be difficult! I think a lot of women are inexperienced, but do "anal for pay" and don't actually enjoy it. When the muscles relax it is easy to go in balls deep, plenty of lube and maybe a bit of anal play helps.
I am over 7" and it's never been an issue for me, but I'd only pick an anal escort who enjoys it, no extras nonsense or "I have a tight ring" nonsense.
In Yorkshire Kimora could take any size, but she was a large lady and I think she's retired.