I was recently at a festival in town and I saw a woman walking a beautiful border collie. I smiled and asked if she would mind if I took a picture of her dog. She scowled at me, turned around, yanked the dog by the leash and walked away!
Have you ever had something like that happen?
Her people skills are a little lacking, but, there I see nothing wrong with her objection to you taking pictures of her dog. As for most of the other incidents related in this thread, it appears the rudeness is coming from behind the camera.
Take candid shots when you are with your family and friends whose permission is nearly implicit, but, I don't think you should be surprised that perfect strangers are going to object to being shot "candidly."
Most of my bar days are behind me, but, if I decided to relax with a few, I know I wouldn't want someone photographing the moment without my knowledge. If you get some really great candid shots in that situation, what will you do with them? Keep them in the camera, delete them, or print/upload them for display?
For the poster shooting gulls at the beach, well, your experience is the price we all pay for the morons who have polluted the 'net with their "candid" upskirt photos and worse.
For a male to venture alone onto a beach where attractive women are sun bathing carrying the "tools of the trade" is to invite a challenge. Whatever your true intentions, take an assistant with you next time - preferably your S.O.
I see absolutely no rudeness in people determined to protect their privacy and not wanting to become the subject of some photographer's candid shots, no matter how artistic your intentions.
Caruso