That's something a bit different and doesn't mean that. A revealed preference means that, if you say you never eat donuts, but when observing your behavior we see you buying and eating donuts, then we know that you actually do eat donuts.

A bias, on the other hand, is if we ask sometime if you want to eat 2 or 3 donuts, and you answer 2, but then after further studies, we see that the amount you eat depends on, say, the size of the plate in front of you, then we know that there's something influencing your decision which you may not be aware of and which theoretically speaking "shouldn't" influence your decision.

Revealed preferences don't mean that everyone makes perfect decisions all the time. It just means that, if you want to find out what people actually want, then the best way to do it is to observe what they actually do.

The other advantage is that revealed preferences tend to be fairly rational. Not 100% and there are systemic issues in them, to be sure, but they're often quite good. In fact I'd say they're reliably better than their criticisms.

That is, given a revealed preference and someone claiming they've identified a bias, I start from the presumption the revealed preference is actually rational and the explanation of the bias is wrong, because, well, the article is clearly correct. I see it online all the time. There's a bias bias, the presumption that if someone explains why something is biased, that's it, case closed, no further analysis needed. I see that bias in myself. It's hard to overcome, which is why I (try to) start by presuming the revealed preference is correct.

People's explanations of their revealed preferences are, by contrast, hot steaming garbage. People are terrible at explaining their reasons. So terrible that I think it actually plays into bias bias, because if you take people's explanations seriously they sound incredibly irrational, so it's merely a matter of trying to explain their irrationality. It seems so fruitful. But while studying patterns in rationalization is probably an interesting topic of its own, studying rationalization shouldn't be confused for studying what people do. In general, I (try to) start out by discarding someone's claimed reasons for doing something, unless they do a very good job of convincing me they're actually good at introspection and have made an at least halfway serious attempt at it.