I am not specifically anti-union, but especially in the US, seniority forces the Airline to keep the older, more senior flight attendants which is why you see mostly 40/50+ year old women as FAs on most domestic flights.
There does seem to be a pretty sour attitude all around although I do think some of that is passenger created. Some of the shit they have to put up with is pretty bad. Doesn't give them the right to be assholes with the rest of us though.
If you want good looking flight crew, fly international with a non-US airline.
I remember back in the 80's flying on Singapore Airlines and every single attendant was a total knock-out. I have heard it is still like that.