I have to agree, knowing why I should give a shit about those people would be a great addition to the list. Did Judy Garland do something revolutionary back in the day, or is she so beloved simply because she sang show-tunes especially well??
I'm not too into GaGa, but she's had lyrics and accomplished activism quite meaningful to the gay youth of today. While both Madonna and Cher have had at least some recent activism, I don't remember anything on topic from them when I was a young fan...?
Liz Taylor is an icon who actually spoke out for us at a time few others were, and isn't even mentioned.