I don't see how that's relevant though. Shouldn't he be promoting Reebok and only Reebok like everyone else?
Look at any major pro American sport... Formal wear is standard for announcers.
Joe wore an Onnit shirt during the weigh-ins to promote his personal business but all the fighters can only wear Reebok, which could be interpreted as UFC being hypocritical. Then again Onnit could be paying UFC to advertise so whatever.
I heard somewhere Onnit was also an approved sponsor. However if that's true Tj Dillashaw would be rocking a onnit logo on his beautiful reebok vale tudos