I'm not going to say if rBST (known most often to laymen as bovine growth hormone) is a good thing or a bad thing for the dairy industry. I'm not going to say if it is harmful to humans or not. I'm not even going to say if it is harmful to cows or not. Mind you, I have opinions on all these topics; I'm just not going to say right now.
What I am going to say is people should be able to choose to avoid it if their little hearts desire. According to this article, some people (with ties to the drug's largest producer, oddly enough), are lobbying to stop "hormone-free" labels.
I could understand, if there were local regulations banning the use of an FDA-approved drugs, lobbying to remove those regulations. Trying to create a regulation against a label that says you don't use those drugs? Unnecessary, wasteful, stupid! Allow people the choice. Maybe this means you lose your market, but that's how capitalism works (at least, in theory): informed people choose where to spend their money. If you can't afford to produce rBST-free milk at the price offered and you can't sell non-rBST-free milk, you need to get out of the dairy business.