Cast your mind back to the start when Jake first came in, and Bullard was in the hut and made a comment about "why did you bring him in?, I'm top dog in here, I don't like him"). he tried to make it look like a joke but it was obviously more than that. I also suspect his pal on the show (Beckett) got word to him about Jake gaining popularity. That's probably what sparked his recent ramping up of his routine, and even more camera hogging, and finally this confrontation. He sees young Jake liked by the girls, liked by all the camp, and performing very well on trials (unlike JB), and it threatens him. He finally snapped. But his attempts to try and disguise it as "banter" were pathetic and creepy.