Howie Mandel and treatment on America's Got Talent?

I understand his disability (OCD) is real. And if that is the case why is he allowed to be tormented on this show. If his disability was something visible would it be OK to make fun of him as is done? Tonight an act brought him on stage and seemed to really upset Howie. He was voted to return with the specific intention in the view of Piers Morgan - to torment Howie further. If this is all just an act - shame on Howie, but if it's not shame on NBC. What do you think?