> It is fair and reasonable to demand that environmental regulation justify its existence with hard, scientifically verifiable data or else get chopped.

This sounds good as a general default, but there are differences of approach. The US, for example, tends to be more permissive with new chemicals while the EU tends to take a more precautionary approach. Which is better on the whole, weighing the various competing goods, I don't know. I generally favor health over economic prowess, however.

> a manipulative political maneuver

Yes, under the pretext of concern for the environment. There are well-known cases where the political opposition will commission a bogus ecological studies to stifle construction projects they either don't agree with or as a petty way to simply make the ruling party appear less successful. And naturally, the ecological study will find something, as virtually no major construction project will leave the environment unaltered, which is not to say seriously or irretrievable damaged.