I enjoyed their music in high school, but I became jaded about the sincerity of their revolutionary message when I realized that they were a major label band.
I think that's a fair criticism but I the counterpoint that they wanted their message to be distributed on a massive wide-scale is a fair point too. They could have went the independent route but there's a reason their music, and by connection their "radical" political message, is still on the outer fringes of mainstream popularity - because they signed to a major label. Political bands that were independent have more credibility but they are completely irrelevant and almost completely forgotten.
While signed to Sony they had full and total creative control over what they released.
Even though they were incredibly popular during their heyday they left A LOT of money on table. They released only three (4 if you consider the covers album) original albums and only performed about 350-450 shows (I forget the exact number) during their initial 9 year run. That is another indication to me personally that the message, through the sale of CDs, and not money was the main (but also not only) driving point of the band.
Also, throughout their time together they had a long track record of playing free shows for benefits, playing single shows and festivals for fundraising efforts, showing up to rallies/protests/strikes to increase exposure, and even donating sizable percentages of entire tours to charities.
Full disclosure: Although I no longer have an emotional attachment to the band, I was a complete fanboy as a kid.