I think that some men act like this for a variety of reasons...entitlement, narcissism, a displacement of responsibility, their own morality (or lack of), objectification of women, dominance.
I also find it interesting that quite often, nobody within a group of men will challenge the behaviour.
I saw this last year when out for a meal. A group of men (all appeared in their 50's / 60's), it appeared to be a birthday celebration from what I could overhear. One of them made several sexual comments to the waitress, the rest all found this highly amusing although it was obvious that the comments were upsetting.
They were drinking - none appeared to be 'drunk' although perhaps that's just my opinion.
As I left, I actually said to the group that I hoped they wouldn't be unhappy about a man speaking to their partner / daughter in that way.....only two had the good grace to look embarrassed!