He is either an idiot who needs to read more and talk these ideas out with fellow marxists before publishing his bad takes or (more likely after looking over a bit more of his writing ) he is a CIA funded stooge.
First article is an example of the fetishization of failed socialist projects. Stalinism was a stepping stone that lead to Maoism. The Russian path after Lenin and Stalin was unstable and ultimately lead into the drink. Juche is just "socialism with Korean characteristics." Using one word instead of Marxist-Leninist-Maoist-Kimism makes plenty of sense. It's like being upset that CERN isn't doing shoutouts to Isaac Newton.
Second one feels like a crackkker is upset that indigenous people don't want americans colonizing them. espressostalinist is twisting the demand to reject colonization into racial supremacy.
Multi-culturalism is a imperialist idea. Its their way of saying "multi-racial" without looking like they are racist. It is used in countries that import workers from nations they have destroyed with exploitation and war, especially in settler colonial states. The implication is that the imperialists are willing to make compromises to welcome other people's cultures and ideas but only if those people are willing to be subsert their culture to be compatible with culture imposed by the ruling class.
There are a few countries made of alliances of multiple ethnic groups like Russia and China but they don't describe themselves as "multicultural." They describe themselves as multi-ethnic or multinational. They don't demand that indigenous people adapt their cultures to the whims of outsiders. They understand that there are existing cultures in geographic regions and that any migrants to those areas is going to have to adapt to the local majority. They aren't trying to impose one single "Multi-culture" on the entire nation because that doesn't make sense.
Not going to bother reading the third more than the first few sentence because it is just going to be more of the same western "communist" ultra bullshit.