I look at it as a form of preventing competition. I mean Worf's adopted brother goes and saves a lesser civilization from destruction, and he gets into hot water for it.
Yea.....better to let a civilization die horribly, but at least its natural development was retained.
Being wiped out in a hideous way is not development.
Also, with oppressive governments preventing said civilizations from developing by withholding information and technology is NOT natural, either (we see that happen today), and what makes THAT acceptable to Starfleet? Hell, there'd be no federation had neither the Vulcan's helped earth, or Picard stopping the Borg.
Prime Directive = Overrated pile of ++++ that is used as an excuse to let everyone else 'eat cake'
And that "you have to have warp travel capability for us, the almighty Federation, to even consider talking to you" is arrogant right there.