One can roughly categorize the opinions here into two camps, those who want Starfleet to be an imperial force as well as a saver of doomed humanoid species vs. those want the Federation to be a peaceful, democratic union and Starfleet to obey their rule number one.
I understand that many people don't understand the Prime Directive and follow their gut feelings but if the Prime Directive were intuitive and common-sensical it wouldn't be as great as it is.
One cannot base interspecies ethics on intraspecies ethics. OK, some species like the Borg or Klingons do it but they aren't the guys you wanna invite for tea.
In the fictional history of Trek humankind was pretty pissed off that the Vulcans did not solve all their problems, that they did not erradicate hunger and war for humankind, that they did not share warp technology. But once the first humans went into deep space they slowed began to understand the Vulcans.
If the "I think with my guts" faction still doesn't understand the Prime Directive, just think about the consequences of some benevolent aliens landing here and forcing us to mothball all our nuclear weapons in order to save us from extinction.