I find it interesting that opposition to rBST largely consists of what economist Bruce Yandle termed a "baptist and bootlegger" coalition. The "baptists" are ideological interests, such as anti-biotech activists and animal welfare groups. The "bootleggers" are small and boutique dairy farmers concerned that rBST can increase the competitive advantage of larger dairy producers. Such combinations of ideological and economic interests are common in environmental law, and can be quite influential.
Living in New England, I've been familiar with the 'milk cartel' based on the extra $1 for gallon I had to pay after moving from New Jersey. For those not familiar, it's a protectionist racket for the New England dairy farmers.