Look, we don't know the context. For all we know he was doing something wrong and was heroically stopped by an inmate. These situations happen in a split second, we cannot judge the inmate for what they did to secure their own safety and the safety of others.

In all seriousness, celebrating the carceral system's cruelty when we are trying to abolish it is inherently contradictory, but most of us are stuck thinking in carceral terms. I'm sure your position is consistent, but people are used to the only time the prison system gets criticized is when a right wing ghoul or offer privileged white boy gets in trouble. So we get this situation where prison abolitionists don't feel comfortable trying to argue "no exceptions" because if someone isn't netting tortured then that's taken as the original harm not being taken seriously... and the harm here was a racist public lynching.