Whether it's Huey Lewis or Bruce Springsteen, the hostility directed towards musicians who endorse or even actively lobby for candidates is misplaced.
First of all, only those who seem to promote liberal politics seem to be so excoriated. Country music has been full of conservative, pro-Bush propaganda and it gets away with it all the time, completely unchallenged.
Secondly, and disturbingly, one of the criticisms against these musician endorsements has been that these people "are just singers," and somehow therefore not entitled to have an opinion. But this view raises the question: are there any other professions where having an opinion should be so verboten? Should plumbers need to keep quiet? Surely not, so why so musicians?
The soundest argument against musician endorsements seems to be rooted in the notion that the celebrity they now leverage to make their opinions widely known was created and bestowed upon them by ordinary people, the fans, under the implicit condition that the fame be only applied to the musical space. Some of the negativity towards these musicians seems to reflect a sense of betrayal, as if being able to make political statements wasn't part of the deal when the fans made the musicians rich and famous enough to be able to command attention to their political preferences.
But this viewpoint trivializes appreciation of their talent. Why appreciate the music in the first place? Is it just that it sounds nice, or is it that there's a reason the music sounds nice? Isn't it reasonable to expect that people with the talent to create fine music might also have the intellectual power to contemplate issues beyond their professional sphere? Particularly those musicians who are known for creative autonomy, whose work represents their own artistic expression - these people may in fact be among the most capable citizens in our population.
And who better to hold a mirror up to us, to make us look hard at the issues affecting our lives but the artists? This is their job! When we instead treat them like circus acts, requiring them to perform only for our iterant amusement, we cheapen their craft and denigrate their talent. We reduce their music to a mere commercial product and deprive ourselves of anything meaningful their musical art could offer us. No wonder we don't want to let them express a broader opinion. Our resentment of them doing so suggests a problem more fundamental, that popular music has become detached from artistic expression. That unfortunate rift may well be the real issue at hand.
Edited 11/6 and slightly more 11/19.