...what gives drug companies legal standing to regulate use?
The fact that they make them and when they sell them everybody down the supply chain signs a waiver (contract) that they will be used for specific medical treatments. They don't make or sell them with the intent that they use be used for capital punishment and the contracts they require as a condition of their sale prohibit that use.
I'm quite sure that the states trying to obtain them for capital punishment don't give two hoots about that, but since the drug companies specifically prohibit their use for capital punishment as a condition of sale then they have legal standing.
If you make something you have a right to regulate it's use as a condition of sale. Don't agree with that use, then no sale. No one has a right to buy something, not even a government.
