Rationalism in philosophy is generally contrasted with empiricism. I would say you're a little off in characterizing anti-rationalism as holding rationality per se in low regard. To put it very briefly: the Ancient Greeks set the agenda for Western philosophy, for the most part: what is truth? What is real? What is good and virtuous? Plato and his teacher/character Socrates are the archetype rationalists, who believed that these questions were best answered through careful reasoning. Think of Plato's allegory of the cave: the world of appearances and of common sense is illusory, degenerate, ephemeral. Pure reason, as done by philosophers, was a means of transcendent insight into these questions.

"Empiricism" is a term for philosophical movements (epitomized in early modern British Empiricists like Hume) that emphasized that truths are learned not by reasoning, but by learning from experience. So the matter is not "is rationality good?" but more: what is rationality or reason operating upon? Sense experiences? Or purely _a priori_, conceptual, or formal structures? The uncharitable gloss on rationalism is that rationalists hold that every substantive philosophical question can be answered while sitting in your armchair and thinking really hard.

> Apparently, rationalism isn't obviously correct. Unfortunately, I don't really have enough of a background in philosophy to really understand how this follows, but looking at how the world actually works, I don't struggle to believe that most people (certainly many decision makers) don't actually regard rationality as highly as other things, like tradition.

Other areas of human experience reveal the limits of rationality. In romantic love, for example, reason and rationality are rarely pathways to what is "obviously correct".

Rationality is one mode of human experience among many and has value in some areas more than others.

there are two facets to "is rationalism good".

one is, "is there a rational description of the universe, the world, humanity, etc.". Some people think there isn't, but I would like to think that the universe does conform to some rational system.

the other, and important one is, "do humans have the capability to acquire and fully model this rational system in their own minds" and I don't think that's a given. the human brain is just an artifact of an evolutionary system that only implies that its owners can survive and persist on the earth as it happens to exist in the current 50K year period it occurs in. It's not clear that humans have even slight ability to be perfectly rational analytic engines, as opposed to unique animals responding to desires and fears. this is why it's so silly when "rationalists" try to appear as so above all the other lowly humans, as though escaping human nature is even an option.

It's stupid, but it works. There are innumerable examples of it, The People's Democratic Republic of Korea, People for the Ethical Treatment of Animals, National Socialism, Mothers Against Drunk Driving. Good guys, or at least people who are good in the context of your or my value systems, also do it. I've got zero beef with my local Humane Society, they're great, but clearly the name of the organization has been chosen for its strong emotional potency.

Or "Clean Code™"