I don’t understand rBST milk

So this says the farmers don’t treat their cows with rBST. Cool, I don’t know what that is but cool.
Then it says the FDA thing which to me means two things:
1. rBST doesn’t mean the milk is bad in a statistically significant way so why does it matter that they pledged not to use rBST
2. Even though the farmers SAID they don’t, we can’t prove it if they actually don’t
Basically, wtf?