Ha, fair question! They have plenty of people they dislike, but what I was trying to refer to was their opposition to what they call "tankies" and I call "People who believe that the US lies about its enemies, particularly its big geopolitical rivals." Specifically, while they are conversationally annoying about it, what really bugs me is their campaign to defederate and get others to defederate from spaces they deem "tankie-friendly". I think that really undermines the platform as a whole to pillarize things that way (i.e. closing things off into silos).

"Sectarianism" arguably isn't the right word for that (it has intra-ideology connotations), but I didn't think it was worth splitting hairs over.