Also, just to make things abundantly clear, gays do not own the anus or anal sex. It is not something we have claimed as our own, forbidding its use by anyone else. Anal pleasure is not exclusively for friends of Dorothy.
Expanding on what you said, if a woman of any sexual orientation enjoys receiving anal that does not imply that she is a gay man, so why should it apply to a man who gets fucked, especially if it's by a woman with a strap-on?