Ignore averages. They are often deceptive, and here as well. Most places in the US have zero gangs, and many places have zero murders.
The question is: why are murders so out of control in certain areas? And the answer is: local policing and local politics. DAs don't prosecute, and so police won't risk their life to bring people in. They show up 30 minutes later as the clean up crew.
So it's actually fairly normal for repeat offenses here because someone is never arrested, never charged, out on bail, plead down to a slap on the wrist, or out on parole where supervision is a joke.
Why are local politics so screwed up? That's an interesting question. One aspect is one-party rule: the Democrats are such an overwhelming majority in a lot of these inner cities that all the politics happen before the ballot is ever printed. Within the Democratic party, there's a dangerous contingent that simply doesn't want to imprison criminals for reasons I don't entirely understand.
Why do the people in such cities put up with such a bad system? Because even within those cities, the problem areas are contained, and can be safely ignored (sadly). "Root causes" sounds nicer than "lock 'em up", so most of the people in the city nod along and go about their business, and avoid the bad parts of town.
My guess is that Ukrainians just don't have time for that kind of nonsense. If someone is violent, they are put away quickly. The idea of making a deal with a violent criminal is probably not fashionable there. There are lots of poor people in Ukraine, and mostly the same skin color, so nobody puts up with the "violence is just a symptom of poverty and capitalism and racism and ten other problems that must be solved first". A few civil liberties probably get stomped along the way, which also helps bring crime down to low levels; but I don't think giving up civil liberties is a prerequisite of law and order.