Except that's *not* how the Federation acts. The Prime Directive is meant to prevent cultural contamination on pre-warp (thus pre-contact) planets, to prevent societies from being manipulated with promises of lofty technology and miraculous abilities. The scenario Sci describes is the Feds acting like a dick, but it's not how they'd act, because said planets are already enmeshed in the politics of the Quadrant, and have been victimized by the Borg and are asking for help. The Prime Directive is out the window. Doesn't mean the Feds wouldn't act like dicks anyway, but the Pact - if they did that - would be intentionally misleading.
The Prime Directive is never out of the window. I may be wrong, but it doesn't stop applying; if I remember correctly, it just loosens and you have a lot more options when dealing with a warp-capable nation. But the Federation is not in the habit of handing out its advanced technology to other worlds. Yes, you're right, in cases where the world in question is warp capable they would help out, offer aid, because that's the Federation we all know and love. But it would be handouts, charity. The Federation wouldn't offer membership and access to the full technological benefits of that Federation unless the world in question met some very strict criteria. The Pact might appear less patronizing and more willing to view the worlds its helping as equals if it indeed operates as Sci suggests. No "we are holier than thou/we'll help but you are as yet unworthy of our full bounty" strings attached to any aid given.