1. Dogmatic adulation of Yudkowski as a "savior" figure.
2. An almost immune response resistance to "practical" approaches to the Friendly AI problem. For example, laying out even a basic path to the structure of one - given that's their mission.
3. In light of #2, the community's serious consideration of un-testable scenarios like Roko's Basilisk
4. A flavor of authoritarianism, racism and sexism from former founder as Michael Anissimov.
5. Critical lack of diversity in backgrounds and approaches to ML/AI, which keeps the thought process fairly insular. For example you never see these people talking/attending AI conferences, and I'm not sure I have ever seen them at the AGI conference. AFAIK also they only publish in-house with liberal internal reference.
Those are some from the top of my head. Granted I think they have sorted some of this stuff out, like #4, but all of it together makes for a toxic and fragile community, largely built around a singular ego.
I haven't been keeping up with them as much in the last few years so some of these things might be getting better - but when I left the community in 2013 these were my main problems.