Respecting one's elders doesn't mean letting them get away with wholesale lying or fantasizing.
Somebody's gotta speak the truth.
.45MAN tried. My father nearly stroked out. My mother asked us not to discuss politics anymore and we acquiesced to their wishes.
I'm not going to have them around much longer and I know I can't change them, so it's something I have to give in to.
Friends and acquaintances are a different story. I don't hold back and have lost "friends" - I use that term loosely because I realize they weren't really friends to begin with. Someone at my former place of work when we lived in Atlanta tried to get me fired for my political views. It backfired on her. That was a beautiful thing to see.