Why do you suppose claims like these, at least in the first world, are always spearheaded by bolshevists, and moreover by rather stalinistic groups?
Anti-sectarianism is all well and good in the abstract, but needs to be based on concrete movements rather than opportunistic defenses of any old leftist regime/group that proclaims the mantle of anti-imperialism or anti-capitalism. When the purported alternatives to a liberal democracy, for example, are actually less conducive to our goals, leftists need the breathing room to call out comrades on it, not be stifled out of some arbitrary cry for "solidarity". For example, when Mugabe's regime sends in the army against striking miners and tortures communist journalists and the capitalist governments issue condemnations, we shouldn't all be expected to engage in public demonstrations supporting Mugabe's autocracy.
Our loyalties lie with the workers and downtrodden of the world. Not with the leftists of the world.