Here’s the contradiction. Sectarians criticize cooperators, but cooperators, try to cooperate, so they don’t criticize sectarians. The result is sectarians get away with their destruction.
Put another way, Sectarians judge well-intentioned progressives as sleazy or evil, but cooperators, do not make the sectarian mistake, so the recognize that sectarians are mainly just confused. Since they view them as well intentioned, they respect them and withhold criticism.
Both the sectarians and the cooperators are involved in an unhelpful dynamic. The only way to break this is for the cooperators to change. They should not give up their view that sectarians are well intentioned, but they should listen to an old and wise proverb:
The road to hell is paved with good intentions.
Sectarianism is truly the road to hell, and it should not be tolerated by the cooperators. This cooperators should speak out and dismiss sectarian nonsense. This is particularly difficult because the sectarians always say they are more “left,” in other words, holier than those they rail against, and this “holier than thou strategy fools many.” But there is nothing holy about the sectarians, and they are generally “more left” in the sense that Stalin was “more left.”