The ideas around some sort of prime directive, are about non-interference and natural development.
But surely this presupposes the definition of natural development, as only applying to the bubble of that planet.
What is natural?
If the Klingons wanted to blow up a planet that would be natural too, in the larger picture, would it not?
So if any aliens are reading this: it would be completely natural, and indead healthier if you made contact. To not do so would be the un-natural decision.