Just because you can't tell the difference doesn't mean you should deceive someone, right? That's a pretty disgusting attitude to take about sex. A neovagina and a vagina are different.

Say a cis woman goes over to a man's house, blindfolds him, and then says she's going to fuck him with her pussy. She puts a condom on his dick and then inserts his dick into her ass instead. He doesn't realize the difference, but he thinks he's fucking her pussy. They finish up and she takes the blindfold off afterward, and he goes on his merry way, never realizing what happened.

Was that somehow ok to do just because he couldn't tell he wasn't fucking her pussy or her asshole anyway?