Bob's T-shirt blurred out in ep 6 (sr1) about 18 mins in. Eh... Why!?

So, just curious as to why bob's t-shirt was blurred out in series 1, ep6 of sober house? What did his t-shirt show that they had to blur it out when they screened it (about 18 minutes into the episode, during the group session at that time)

Anyone have any idea as to what it was that they blurred out plz?