There is really no comparison between the Idaho case and the Chicago case. I understand people are trying their best to do so - Twitter is filled with people trying to compare the two cases. But there really is no comparison.
In the Chicago case, the kid was kidnapped and held for more than a day, during which he was tortured. Had the downstairs neighbors not called the police because of the noise, and had the thugs not gone downstairs to assault their neighbors, the kid likely wouldn't have escaped.
The 18 year old girl is in a photo (I believe at a different time) holding a handgun, so there's a chance this kid may have been shot and killed at some point by these thugs.
In the Idaho case, you have a couple guys who shoved a hanger into the anus of another kid. As awful as that is, he was not kidnapped, tied up and tortured for more than a day. It was a horrible crime. Were I the victim's father, I would be angry with what they did to him. I would also be angry with the deal which was made with the prosecutor's office. I would definitely seek civil suits against the families of these thugs and the school.
But there is absolutely no comparison between the two cases.