Admittedly, I didn’t follow the link (pages usually filled with pop-ups and ads)but from the sound of this excerpt, the UN is being called to police the police, not the bands of gangs and murderers in Chicago.
I think it’s going to end up as “blue helmet bingo”, as the gang bangers aren’t going to pass on those colorful targets.
About the only way UN troops have effective is in “meals on wheels” functions, etc.
You’ll are missing the main advantage. When the UN troops rape and pillage it will add to the gene pool and stop some of the inbreeding.