Am-Suisse,
I agree that society isn't as civil as it once was in a lot of cases and I did my best to teach my kids to hold doors, defer to elders, and be polite in general. All this can be done preferably without using any other form of address besides the person's given name or Ma'am or Sir, or even (horrors!) no proper noun at all! I'm terribly sorry for stepping on your toe means just as much as I'm terribly sorry for stepping on your toe, Hon. Perhaps even more.
I disagree with your opinion that when people call you diminutive names, they're doing it with the best of intentions. Some are, certainly, but others do it to place themselves above you (or me, as the case may be). Or they do it to make you THINK they're calling you baby names because they care about you when they're just trying to make a bigger tip. It's phony at the very least.
You may think I'm a witch for being militant about strangers calling me terms of endearment in restaurants, but you ought to hear me when the subject comes up about nurses and aids calling their patients cute names.