Nice, Bert! Nice originally meant ' foolish, ignorant' (it's from the Latin word meaning 'not knowing'). Nice people were so nice that they had it mean something else (as I used it in my opening words).
And as for mispronunciation! People talk of someone's special strength as his forte, pronounced 'fortay' ? It should still be pronounced 'fort', as it was originally French. They pronounce the term in music, meaning 'loud', 'fortay' too, but that's correct, as it's from Italian. (i don't make the distinction either. It would now be thought eccentric or pedantic to do so)
Unfortunately, demotic is democratic. When the majority decide, in their ignorance, that a word means something different, that's what it means.
(I got through this whole thread without quoting Humpty Dumpty. That's an achievement!)