I'll say it. Spock's interpretation of the Prime Directive is dumb. I'm assuming that these people are not member states of the Federation. Why does the Federation have any obligation to stop a natural disaster on this planet and risking crew and ship, besides emphasizing the fact that these people are the "good guys". Spock's there spouting off not revealing themselves at all, even preparing to sacrifice himself for the Prime Directive (after they've already seen Kirk and Bones, by the way), and yet at the same time Spock seems to think Starfleet and the Federation are the Galactic FEMA.
They better have a good reason why they're protecting this culture, like some politics or something, or I'll be really disappointed. The Enterprise being there doesn't make any sense with the Prime Directive in place, and right now it seems like it's there simply to set up the first action scene in the movie.
EDIT: And why can't this device be activated remotely anyway?