First I will say that I did not read everything posted about this topic.
I am currently in an ENT rewatch and just saw this episode the other day. I have also had this discussion a few times. Here goes:
Though I don't know if I could have done what Archer did, I think what he did do was right. He was smart enough to have a "prime directive" before there was such a thing. Maybe listening to what T'Pol had said in the past about interfering sunk in.
I see both sides of the story but I would have sided with Phlox and Archer on this one.
Why? They made the most wrong decision it was possible to make. An absolute bullshit decision based on hokey pseudoscience.
Evolution doesn't have a plan and doesn't have a goal. And you certainly can't predict the path it's going to take in the future.The Enterprise, Phlox and Archer are as much a part of nature and the universe, as the disease that was killing the people of Valakis.
The argument for witholding the cure essentially boils down to "mother nature wants 'em dead"
which is utter nonsensical horse shit and ought to have no place in a serious sci-fi show.
Archer is a murderer.