C.R.E.A.M. by Wu - Tang addresses this. The song is about how they went from being drug dealers to preaching to kids how gang banging and drug dealing isn't the way. They made a lot of money doing that too, deservedly so. Corporations and cash for that matter are not inherently corrupt. My point is if people really listened to Wu - Tang they wouldn't be corrupt drug dealers even if they sold legal drugs.
Point about RATM still stands. Not because "all corporations are evil — of course not — but because RATM preaches exactly that "all corporations are evil".