Christopher I would like to bring up Prototype.
A warp capable society of robots in possession of technical level of sophistication that exceeded the Federation, who were incapable of reproducing, so were dying off as a "species". However it seemed they found salvation when B'Elanna Torres claimed that she could set them right and save these droids from extinction.
JANEWAY: I don't doubt your abilities, B'Elanna, but helping them reproduce is a clear violation of the Prime Directive.
TORRES: They've expressed a desire to procreate. That's basic to any life form.
JANEWAY: I'm not saying they don't have the same rights as any organic species. That's not the issue here.
Janeway saved the Borg from 8472, and Arturis' bunch got decimated and he took revenge on Janeway for saving the Borg.
What you have to remember is that the Prime Directive is General Order Number in the Starfleet Rule book, not first stipulation on the Federation Charter, similar to how I assume that you are not constrained by the US Military Code of Justice. Of course Starfleet has to obey the dictation of the Federation Council who can answer aid requests from any one and then send Starfleet off to save the day... Chain of command? The Council orders the Admiralty and the Admiralty orders the Captains but a Federation Councillor or the Council et all can't order a Captain to do Jack shit? Imagine a Congressman assuming command of an Nuclear Submarine to impress his callgirl? But the Admiralty and/or the Coucil can repeal or supersede the Prime Directive by ordering/allowing humanitarian aid to "alien" factions which mere Captains have to stay to one side of unless they are on an "approved" list, and close to home like Picard's Enterprise was mostly, there would most certainly be a Denied list as long as any approved list that he was not allowed to make any contact with at all like how Christian Scientists won't take blood transfusions when they're dying.
Janeway doesn't have any list of approved and disapproved states she can play with, but even when she's dealing with nice Aliens, the Prime Directive protects her from the culpability of unforeseen consequences, and what would these unforeseen consequences be in the case of the curing the Phage? Oh, that's right, how can you foresee the unforeseeable? THAT'S WHY THERE'S A RULE!
Oh. Remember the Malon? Voyager offered them recying technology that would have stopped them from turning half the quadrant into a cesspit, but the garbage men weren't interested because if they couldn't haul garbage then they would be on the streets and living in incredibly clean gutters.
Tom saved that Water "planet" by blowing up a power plant against the wishes of the local government, which Janeway agreed with, but still refused to hand Tom over to suffer at alien justice for acts of terrorism, which is similar to what Teacake suggested about forcing a civilization to accept Federation aid.