Lemmygrad is specifically problematic for being predominantly Marxist Leninist (as the .ml suggests). I think you're probably right that people just reject them outright because of AH THE COMMUNISTS WANT TO END CAPITALISM red scare type stuff present in Western countries, but where I specifically find Lemmygrad (and other tankies) being way too negative to interact with is when they get into defending Communist regimes.

If you asked the average Lemmygrad user, they too would be enveloped in propaganda, though this time coming from communist regimes and praxis they've read. They have been deluded into believing Stalin and Mao were good leaders, that authoritarianism is okay if it advances their favorite political agenda (though for some reason also claim that these countries aren't authoritarian), and that these regimes should be implemented everywhere.

The worst of it all is their constant genocide denial. Yes, the USA and other Western countries have done a similar amount (maybe even more?) of really bad stuff in this area (e.g. natives, apartheids, roma, etc. 💀), but I think broadly a well educated Western citizen, especially a leftist one, should be able to understand and admit that what their country did was wrong and should never be done again. A Lemmygrad user instead defends things like the Uighur genocide and Holodomor, saying both that they don't exist and are "western propaganda" while at the same time entertaining the counterfactual and saying if they did happen it was justified because the West did it too and they were being very mean to communism 😡.

When you get to that level of malevolent stupidity, you start to look more and more like a fascist that supports genocide and absolute power of the state and that uses strategic ambiguity to express your toxic beliefs, than you do a leftist. I don't think anyone suggests we stay federated with a fascist instance because fascists are misunderstood after "years of propaganda pushed by western countries" to discredit Hitler and Mussolini, but here you are doing the moral equivalent.