Actually it has never been proved to harm anyone or anything, including the cows given it. But let's not let facts get in the way of a good smear.
Oh and by the way because of the < bleep > storm kicked up by these people rBGH is rarely if ever used any more.
Which is partly why the cost of dairy is going up and up and up.
Actually, rBGH has never been proven to increase net production. It has been proven to increase mastitis and reduce the overall productive lifespan of cows.
The cost of milk is not the result of Luddites, but over-regulation by agencies without oversight and government market intervention.
Conservatives are generally opposed to both of the latter.