It is a tough decision, do you reward someone who is a known criminal? However, I would prefer to keep things simple and not include his professional life with his personal one. Yes, he did some terrible things, but as an athlete he was amazing and deserved to be in the hall of fame.
People convicted of violent felonies should not be allowed in the Hall of Fame. The Hall of Fame should be intended for people who excelled on and off the field in excellence. It is no argument to say that O.J. Simpson excelled on the field. His off the field actions however warrant him unworthy of any adoration.