I doubt the attacks are racially motivated. In this instance, the autistic kid had new Nike shoes. The Sudanese demanded that he hand over his shoes and wallet, then bashed him when he refused. A few days ago the Asian deli owner who put up the "no black" sign out the front of his store was forced to explain to the left why he wasn't racist. Some of the footage from his security cams showed a group of around 8 Sudanese blatantly stealing stuff. When he confronted them they threatened him and said, "don't touch this [the stolen goods] is ours now."
The violence is for two reasons:
They can use violence and crime to enrich themselves and align more with the US ghetto culture that they're trying to emulate (most of these listen to gangster rap and dress like US gangsters). They openly boast about crimes on Facebook and in their social group, the more serious the violence the better their reputation is with their peers.
They know that, even if they do get caught, the punishment is going to be laughable. (No disincentive)
