Well then put on your mask, and give them the antidote as if you were one of their own. I mean siriously what is more important? Lives or possible damage in the far future.

btw.. i truly hated the episode where archer decided to not help to create cure, because this other species has a change to become superiour and all that stuff.. It was the episode where two different species have "evolved" from the same planet and the superiour race is getting ill and will die in the future if nothing is done. The views and ignorance of some people is just stupid (i'm talking about the writer(s) of that episode, don't know who is it..)

In my view it is hyporcytical to judge if someone is worthy of survival based solely on the stage of their development. It should make NO difference to Star Fleet which stage of development a sentient being has achieved; they, always and without exception, have two options: Help them or not help them.

In that respect the only difference between the Federation and any other empire is that the Federation has enough birocracy to have the image of wanting to help everyone, but also having enough exceptions in those rules, not to do so.

The episode from ENT you speak of iwulff.
Now that ep had nothing to do with the Prime Directive! I mean, they just went to the planet oblivious as to what's going on, got FAR too involved and in the end did nothing to help either species! Archer was in no position to decide on the fate on either of those two races. That ep just made me think Archer was an arrogant prick.
Still, you have to consider humanity had never faced such a God-like decision. I'd think they were in a transition between of ways of though. On one hand the natural instinct to help a people in need and on the other, all the new philosophy the Vulcans had been putting in their minds for the last 90 years.
Archer simply tried to find (key word, tried) a balance, his IQ aside.