When prisoners accept Christ in prison it is with a sense of repentance, sorrow for what they had done and a conviction to accept responsibility for their past actions and turn their lives around.
When prisoners convert to islam in prison, there is no consideration of repentance. Islam gives them all the excuses they need to blame others for their plight, foment hatred (and violence), indulge their infantile sense of self esteem (such as it is) and demands for ‘respect’. The LAST thing islam will ask of them is to reconsider their past actions or take personal responsibility.
In my 25 years in the California prison system, I saw a few (very few) inmates truly repent and show the fruit of the spirit. The vast majority of inmates who were in the chapel program, were there to avoid most (not all) prison politics, like gang banging, drug trafficking, and other criminal activity, as the other inmates generally left them alone. I sat in on a few "Bible studies" and I was amazed at all the anti Biblical stuff coming out of their mouths. When they paroled, for the most part, they left the Bibles at the gate.