Maybe? It doesn’t square with my personal experience, at least. I went through the usual spiel with someone last night, without knowing whether that was going to be a deal breaker, and I very easily could have avoided that problem, because (1) I’m a good liar, or at least I was back when I let myself do it, and (2) this person and my SO live in totally different cities and run in completely different social circles, so an alternate version of me who’s willing to cheat and lie would have no reason to think that keeping this particular secret would be hard to do.
On the other hand, my father lied a lot and much of who I am today is basically An Attempt At Being Not-Him, so I might have a Weird Reluctance To Lie for reasons other than “am a nerd.”
They aren’t rationalists per se, and don’t seem to overall have a high opinion of rats (though they’re also willing to paint a better picture of e.g. Scott Alexander than e.g. r/SneerClub paints, so it’s probably best to not confuse the two), and they’re willing to get personal and ad their hominems.
However, while I’d give them less credence than Wikipedia (which has issues of its own, as we’re all aware), that doesn’t mean that I ignore it entirely. Maybe it’s because I grew up in a cult, but RatWiki is really nice to visit every now and then, for much the same reason that I still visit r/exmormon every now and then. Also, it keeps a better list of cranks and scoundrels (and their cons and scandals) than Wikipedia, so I also use it every now and again as a(n initial) resource whenever my parents mention some person or thing which I’m pretty sure is bullshit just by the sound of it.