Pen Pals opens up a dumb can of worms, so we can assume, probably (From The Drumhead), that SF looked the other way because Picard saved the planet...from a NATURAL disaster...and without contamination.
Well what about the poor slob Captain one sector over who obeyed Starfleets "most precious regulation" to the letter when he finds out 'Oh heyyy...those billions of people you let die and will carry to your grave? Yeah...Starfleet really doesn't care one way or another."
The ONLY way all this works is if Prime Directive 101 is taught at the Academy as a philosophy course and not a strict set of regulations. "Every Captain must make his own decision, no two cases are alike."
edit: I also find it hilarious that the only thing standing between aliens swooping down and solving all our problems for us, is that...no one has thought to ask.