If i've owned that company I wouldn't have a bodybuilder either...Why endorse a person who is using massive amounts of drugs(probably conservatively 25x that of any other elite athlete) and can be busted at anytime because their whole life revolves around said drugs? Not worth it anymore...
The problem is if these companies don't endorse bodybuilders no one will buy their protein powders and creatine and whatever other test booster bullshit they sell. Regular people who watch sports have no interest in working out and taking supplements. So when Joe Blow sees that his favorite football player or baseball player is sponsored by Muscletech they won't even give their products a thought since protein powder = steroids in their eyes.
Another words, the only people who want to buy protein powders are people who follow bodybuilding.