//why do men think it is OK to ask her such questions //
I cannot answer in this particular case as full details, from both sides, are not available that I can see.
However, from experience, I would suspect it is too much booze coupled with banter that has gone too far. Whilst not all the time I have seen barmaids/waitresses who appear to encourage this (and not just in this country).
"Respect". Correct, but some women do need to understand respect is earned, unfortunately you have some letting the side down.