For 2, I disagree - you may want chemicals in your well if they’re designed to counteract the poison that was already in there. See 1.
In 4, 5, and 6 it seems you’ve lost sight of the fact that the analogy is being used as an argument against something that’s occurring in the real world. Whether my counter argument perfectly fits the original analogy is irrelevant because I’ve merely co-opted it as a rhetorical device. Are you suggesting it doesn’t fit with reality?
For 7 and 8 I’ll just emphasize that the ethicists were employed by the chemical manufacturing companies. A conflict of interest is not a great foundation to build on.
> no ethicists is probably worse than fallible ethicists
How fallible are we talking here? “Probably” is carrying an awful lot of weight in that argument.
> You want to deflate the wallop this analogy packs, but I don't think you succeed.
That’s just like your opinion, man.