He says an even more important thing: the Prime Directive is supposed to protect THEM. Whatever they do, eventually they are responsible for the fate of the civilization.
This is ultimately the whole point of the PD, as I see it. It's not really about those cultures out there at all, no matter who is professing otherwise. The main concern to them is how interfering affects THEM. It's a danger to them to be meddling in the affairs of other worlds, as well as a danger to the world's natural development
However, certainly no rule should be completely black & white, & if you're willing to let the Enterprise create its own life form, to send "on it's merry way" for god sake, then perhaps if you're in the neighborhood, & can spare some doomed primitives, it's not going to be any riskier
At least they're not dead. I can get behind that, even if on paper, we don't set a mission goal of seeking out primitives to save, which would be beyond possible
So yeah, the episode betrays some of what we know about Picard. Picard is humane above all else, & the humane thing to do is help them, but he turns his back on his own humanity for a rule, & only helps when given no choice by an agitator. That's not usually the way he acts, as evidenced in Pen Pals, where he actually chooses to act, with much less rebuke