I agree with both your assessment of the most likely reason for lack of seeing the boyfriends/girlfriends on the air, and the reason for the response to your question. It seems pretty likely to me that they also picked the people who had the prettiest/most generally socially acceptable girlfriends. TV just isn't that open to diversity and I really can't see John being a judge having ANYTHING to do with it - not really. He's already a known entity.