You would think that would be the last thing someone who had experienced jail would want to wear when they no longer have to. Could he actually be "homesick" and fondly reminiscing about his time in jail?
Or not want to deal with the pressure of having to pick out his own clothes? Or maybe jumpsuits are just that comfortable to him?
Also, I can picture some very stressed public relations/marketing person for the mall seeing this and not wanting the mall to have that kind of publicity.