Does Mahler's antisemitism matter?
Do you care if Ted Nugent is conservative, or if Bruce Springsteen is liberal?
Alice Cooper is a Republican, and I hear so is Kid Rock.
Does it matter?
For that matter, does Sinatra's beating up chicks affect your listening habits? Michael's pedophilia? Elton or Freddie Mercury being gay?
To try to answer my own questions...
Dixie Chicks went beyond the call of duty and came off as low class and it affected my opinion of them.
Michael Jackson's proclivities gave me the creeps, but I didn't real like his sound in the first place - except I liked PYT, The Way You Make Me Feel, and Gonna Be Starting Somethin'...and then liked them less because they then reminded me of such a creepy guy.
The others, I don't really care what their politics were/are.
(Pete Seeger and Joan Baez are a little overboard for me, too.)