Undercover federal thugs shot and maimed a man in a wheelchair who had come to the aid of his brother, whom the thugs were attacking. They did not identify themselves as cops until after.

People should not be killed or maimed for coming to the aid, with or without a gun, of someone being attacked by unknown strangers.

The fact that this victim was homeless doesn't alter the issue. Neither does the fact that he already needed a wheelchair for some other reasons. Those are misfortunes, and a better organized society would spare people the first of the two, but if the thugs had done the same thing to a fit and healthy home-owner it would have been equally unjust.