Aging, embittered, never was actresses and comediennes grasp at the lifeline of leftist political activism to try to regain the spotlight. Piper Perabo, Alyssa Milano, Kathy Griffin.. I know you can all add to this list, so let them fly!
I think it has more to do with being let down by men. Bette Midler, Kathy Griffin, Ellen Barkin, Streisand (maybe), Cher (though she was probably rougher on guys than they were on her), Gillian Anderson (though she wasn't as strident as the others), Sarah Silverman.
Some of them do have things to be bitter about, when you think about #MeToo Hollywood sexual scandals, and the fact that men of their ages get more and better roles.