I'll never forget the admonition of my professor of "Speech" (an unfortunate replacement for "Rhetoric") at the use of the verb "quote" as a noun by one of the students:
"When a word loses its specificity it loses its meaning."
My 1958 Webster's lists "quote" as a noun only as a colloquialism. My 1967 Random House dictionary gives it full "noun" status. Anybody use the word "quotation" any more? A piece of the language died.
You complain that "suck" no longer means its meaning. Having been removed of it, it is no longer an epithet. So if "mean people suck," so what? (I know a couple nice people that do that, too.)
I don't know what is the significance of the bumpersticker. I am 'mean' by two of the uses of the word and enjoy oral hetero-intercourse. Are they trying to disparage or insult me? Do I give them the five-fingered wave and let them decide its meaning?
Or do I draw my sidearm, an armed society being a polite society?