You'll need to send a referral to the PPP Mr. Waines
As always nostalgia, although I am lost like you as to it. I remember seeing it as a kid, with my mother and I didn't understand why she didn't like it. But unlike carry on films, I soon grew out of this sort of humour.
But perhaps if you look at them as the American version of carry on, then it might help.
I have a friend who believes King Frat is the greates movie ever made, so figure that one out.