Many men decide it is better to become an abuser rather then be abused. A few were violent abusers of women on the streets and pray on weak smaller males in prison. To them dominance is everything. When they have sex it is to dominate and humiliate and they receive pleasure from this. Many of their victims are traumatized for life.
All prisons have certain things in common.
All people who are held captive against their will have similar feelings to varying degrees, but prisons very widely in the way administrators monitor and control inmates activities. Large overcrowded institutions cannot monitor and control all inmate activities. As long as the inmates are being fed, clothed, receive minimum medical services, and are not killing themselves, or the officers on a large scale, the administration is satisfied. Sexual practices are ignored in these overcrowded prisons. Prison administrations are as different as the individuals running them.