I believe there was an article on Overcoming Bias about how people frequently use consequentialist logic to support their beliefs, when their underlying reasoning is anything but a dispassionate analysis, and I think that logic applies to Picard's quote.
The justification for the Prime Directive that has appeared in multiple episodes I've watched (I have been watching all of the episodes, starting with the original series and now several seasons through TNG) is that we need to see if these societies are able to successfully "develop" past the stages of evil and become enlightened societies. I don't ascribe moral valence to societies, but to individuals, which is why I think this sort of social Darwinism is nothing short of barbaric. We already know from real life that there is no significant biological evolution after humans developed mature civilizations, and yet we are to believe that the right moral choice is to let these species "evolve naturally" to see if they are worthy (they are allowed to know of Starfleet once they have achieved warp drive technology). If these people are biologically capable of advanced moral thought, that capability exists whether they are currently exercising it or not.
The basic question is whether you think the world would have turned out better or worse if you could go back several hundred years and tell humans, "Hey, this slavery thing is not so hot, it really doesn't work out well," and other moral truths that we take for granted. This is aside from the situations where they are directed not to intervene even when, for example, a star's collapse is going to destroy a civilization made up of billions of individuals that have moral valence, through no particular fault of that society and having no bearing on whether they will achieve Starfleet's preferred standard of morality. I find the idea that it is universally negative from a cost-benefits perspective to "interfere" with a culture's development, such that this becomes the first and most important rule of Starfleet, to be utterly preposterous and morally repugnant, as well as a hilarious injustice to individuals in the name of judging them based solely on their group membership.
Of course, I acknowledge that it's not "about" that, in a way. The real purpose of the Prime Directive is for Gene Roddenberry to aggressively signal how much he disagrees with imperialism which historically occurred on Earth, but it makes no in-fiction sense, given their supposedly advanced levels of moral development and superior anthropological knowledge.
I don't ascribe moral valence to societies, but to individuals, which is why I think this sort of social Darwinism is nothing short of barbaric.
Reread that sentence. Notice how the second half seems to contradict the first.
We already know from real life that there is no significant biological evolution after humans developed mature civilizations,
We do? This is not at all obvious. Consider the generic changes in domestic animals, for example.
...If these people are biologically capable of advanced moral thought, that capability exists whether they
Disclaimer: I am not a philosopher, so this post will likely seem amateurish to the subject matter experts.
LW is big on consequentialism, utilitarianism and other quantifiable ethics one can potentially program into a computer to make it provably friendly. However, I posit that most of us intuitively use virtue ethics, and not deontology or consequentialism. In other words, when judging one's actions we intuitively value the person's motivations over the rules they follow or the consequences of said actions. We may reevaluate our judgment later, based on laws and/or actual or expected usefulness, but the initial impulse still remains, even if overridden. To quote Casimir de Montrond, "Mistrust first impulses; they are nearly always good" (the quote is usually misattributed to Talleyrand).
Some examples:
I am not sure how to classify religious fanaticism (or other bigotry), but it seems to require a heavy dose of virtue ethics (feeling righteous), in addition to following the (deontological) tenets of whichever belief, with some consequentialism (for the greater good) mixed in.
When I try to introspect my own moral decisions (like whether to tell the truth, or to cheat on a test, or to drive over the speed limit), I can usually find a grain of virtue ethics inside. It might be followed or overridden, sometimes habitually, but it is always there. Can you?