There are some good arguments for and against how the PD is interpreted . But the main problem I have is the mixing of pseudo science with it.
In Pen Pals, Data made contact with a little girl from a pre-warp society, whose planet was about to tear itself apart.
Data suggests that it might be possible to save the planet without
any contact with the inhabitants, but here is the response;
DATA: If we can determine the cause of the geological instability, we might be able to reverse the process.
PICARD: And violate the Prime Directive.
Even if they could save those people without any risk of contact, it is still a violation?
But the real new age/philosophy part occurs later during a conference about the situation.
RIKER:.... We would be gods, but we're not. If there is some cosmic plan, isn't it the height of hubris to presume that we can, or should, interfere?
GEORDI: So what are you saying? That the Dremans are fated to die?
RIKER: It's something that needs to be considered.
When they start using words like "fate" and destiny with what is supposed to be an non interference policy towards aliens, the (TNG) PD starts looking a little weird.
So according to this the criteria for deciding to help a culture in danger is whether they are warp capable or aware of life on other planets--if they are, they deserve to be helped--
If they're not, then it's their fate and they should not be helped