Part of that's because LW redefined rationality to mean something different than it means out there.

At the last weekend I was at a birthday with a lot of LW people where we did lightning talks. One speaker made the point that he programs better when he shuts off his emotions because his computer doesn't care whether he's angry at it. Even when the software tries to get him to feel pleasure by being pretty that draws him out of his analytic programming mode.

There are people for whom striving to become more rational involves focusing on the analytic mode. Thinking about the tradeoffs is useful. Having words for them is as well.