The entire community is extremely insular and is weighed down with it's own established ideas. Most of the writers speak with total conviction, absolutely convinced of their own conclusions, despite the entire point of the endeavor being the pursuit of ever increasing amounts of correctness, thus making them 'less wrong'.

It consists mostly of extremely narrow demographics, cutting it's objectivity off at the knees by creating a culture that is perfect for serving as echo chambers despite their criticism of one another. It has also engaged in censorship of ideas, something that CANNOT be allowed in a group that is trying to further rational thought.

Aside from that there is also the personality cult surrounding Eliezer Yudkowsky. Objectivity is impossible if people weight the merit of your arguments by your popularity, which is inevitable in such a situation.