I’m saying this as a member of several minority populations, but I too am unsure of the efficacy of these types of programs. It reminds me of court-ordered treatment, or anger management therapy. If you just sit in a room and listen to someone, the chance of a behavior overhaul is minimal, is prejudices already exist.
If someone is completely naive about sensitive interactions between groups, though, I think they could get a lot out of it. Things like not using a group’s adjective as a noun (“Look at them gays”) are easy to pick up, and an easy way to recognize individual identity.