It's such a strange idea. Being a musician is doing your job. You get paid to do things. Would you call a bricklayer a sellout because he simply laid bricks where people told him to? In days gone by, the whole point of being a musician was to entertain, and to write music that people would want to listen to. What is wrong with that? If you like the music, why do you need to say whether or not the band are "sellouts", and if you don't, what are you listening to their music for?
Don't get me wrong, I admire people who have artistic vision and who pursue it no matter what, but I don't understand how I am supposed to put myself into a postition to judge someone esle on what route their career should take. I think it would be a shame for anyone to put out an album that they didn't like, but again, who am I to judge?