This is what always gets me about the idiots who say that "oh, my gyno couldn't tell the difference with my designer neovag, tee hee!" Among other misconceptions, they have no idea that the vaginal canal is visibly lined with rugae: ruffled folds that provide the excess skin needed to stretch during delivery. (It's the same sort of structure that allows for temporary expansion of the stomach after a large meal.) Because yeah, it's a complex organ that covers many different functions and has the parts to support all of those many functions.
From their view, if it's a hole between the legs that can be penetrated, it's a fully-functioning vagina.