They may be shiftless when left to their own devices, but the Bolsheviks who are eager to use them as cultural foot soldiers (also known as Useful Idiots) aren't. During the Red Terror in Russia, the Bolsheviks made a practice of bringing in thugs from different ethnic groups, depending on what area they were operating in, because these outsiders were less likely to allow sentiment and empathy to get in the way of carrying out their assigned tasks.
This whole situation is complex, but what it boils down to is multiculturalism. We are seeing the fruits of that poisonous ideology, carefully planted by the Left all those decades ago. This is just one example. There's going to be more, a lot more. We are more and more resembling a post-colonial country, where different groups were arbitrarily lumped together under one State and within a single border, and a near constant state of strife exists.