I don't think the Sequences are that dangerous, because they spend a lot of time trying to get people to see problems in their own thinking (that's the entire point of the Sequences, isn't it?).

Also my limited experience from LW meetups suggests that people who come there only for the feeling of contrarianism usually avoid reading the Sequences.

Probably for the same reason they also avoid reading a serious textbook on the subjects they have strong opinions about. (I am not saying that the Sequences are a serious textbook, but rather that the dislike towards textbooks also translates to dislike towards the Sequences and probably anything other than sensational online videos).

Thus, ironically despite various accusations against Eliezer and his education, the Sequences can act as a filter against crackpots. (Not a perfect filter, but still.)