that beliefs about what reality contains should always be formed on the basis of evidence or rational argument—so that “faith” is inherently an unethical way to form your beliefs.I have to disagree; or, to agree, I would have to construe "ethical" much more broadly than I prefer.
I definitely agree that forming beliefs about reality on any basis except that of logical analysis of perceptual evidence is stupid. But I doubt whether stupidity is specifically unethical, especially in the sense suggested by juxtaposing belief formation with "cruelty, tyranny and oppression".
First, my preference is for small-ell libertarian humanism: I intrinsically value my own freedom, liberty and individual autonomy over more prosaic, material considerations of happiness and suffering. If I'm not "picking your pocket or breaking your legs," then no matter how stupid you think I am — while you're more than welcome to volunteer that I might be somehow mistaken — I'd just as soon you would STFU and keep your ethical judgments to yourself. Since this is my own preference, I don't volunteer ethical judgments of other people's private behavior.
Second, I think it's disadvantageous to bring belief formation into the ethical arena, since most people's belief formation mechanisms are — in my not so humble opinion — stupid. For the thousand years that belief formation was an ethical principle, the Christian Church dictated our beliefs. We've spent five hundred years changing those ethics, and we're still not done.
How would such ethics of belief formation be enforced? If it shouldn't be enforced, why should the ethics of belief formation be different from the ethics of "oppression, tyranny and cruelty"; I definitely approve of enforcing my ethical beliefs about the latter. Should our ethics be minimal, that everyone should just pay lip service to rationality, or do we want to enforce a condition of sufficiency? Since we can't have perfect sufficiency, where do we arbitrarily draw the line? Who decides? If we put it to a vote, religious thought will be approved; without a vote, who gets to be the tyrant?
Stupid belief formation can and does cause conflict, but why not simply restrict our ethical beliefs to those conflicts? I don't need to have an ethical opinion about your beliefs to protest the oppression those beliefs might entail, and I can end the oppression merely by insisting you keep your stupidly-formed beliefs private, or at least restrict them to the area of free speech.
On the one hand, if we restrict "ethics" to instances of material conflict between individuals, different belief formation mechanisms are not per se in such conflict. On the other hand, if we apply "ethics" as an umbrella to cover stupidity, personal beliefs, and unenforceable preferences, as well as actual conflicts, I think we water down the concept of "ethics" and erode the already fragile connection between ethics and law.
It's better, I think, to except belief formation mechanisms from the domain of "ethics". In the long run, reality itself will take care of people with beliefs at odds with reality; reality no more needs our assistance in this regard than does God.