After all, if we defined "superstition" in the Roman Empire as animal sacrifices to gain favors and "religion" as the worship of pagan gods, the victory of Christianity there was an unparalleled triumph of reason.

I've got two answers to that:

1) I think you've got an insufficient understanding of either Christianity as it is practiced or of polytheistic religions, if you think Christianity is a major improvement upon them rationality-wise. An animal sacrifice was the ancient equivalent of modern 4th of July fireworks.

2) Suppose I'm wrong about (1) and you are right that Christianity is in some way less superstitious and more grounded in reality than the pagan religions that it supplanted. Would the spread of Christianity not then constitute a weakening of superstition, in accordance with what we'd expect to pair with technological improvement?

The modern conception of race and gender equality is absolutely superstitious

I think you're stretching the use of the term "superstition" to encompass things you don't agree with. In my opinion, the psychology of superstition can be summed up with this paper - it describes a specific subset of beliefs.

1) Most people believe there is evidence that no genetically determined behavioral differences exist between races. That's not a superstition - they assign a probability to the evidence being out there, just as they assign it to global warming. (For my own view, I would say "racially-correlated genetically determined behavioral differences should be considered considered possible, but there is currently insufficient evidence to make strong claims about the nature or magnitude of any supposed behavioral differences. I think the "race realist" crowd, who thinks that we aught to shape policy around this, is ridiculously overconfident.) You can call them (and me) wrong, but would you call us superstitious?

2) Political race and gender equality would be better termed "race and gender egalitarianism". It should be thought of as a value, not as a fact. It already is demonstrated that gender-correlated-genetically-determined-behavioral-differences exist, but that doesn't really destabilize the main point of gender egalitarianism at all.

Race-gender egalitarianism essentially says: Even if there are group behavioral differences, individuals should be judged on their own merit, rather than by the category they might be assigned to. To see why people might think this is a good idea, just think of any trait you have that happens to be correlated with something negative that you don't have, and then imagine what would happen if people started basing public policy around that trait.

I think what you meant to say by "superstitious" is that people's beliefs surrounding that topic might be biased by political motivations, and I wouldn't disagree.