It's a shame Angie or Yvie have never been paired with Justin in a trial. If they saw how supportive he was they might understand that it's not a coincidence that he always wins the stars (and that they have something to eat*). They probably just think he flukes it.
*Justin was so pissed that Tahir and Richard ruined the food, and he has every right to be.
The show tries to use scenes like this to show him in a bad light, from the editing down to Chris and Julia's constant nasty comments. Justin is the only contestant that Chris bitches about, it's not a good look.
Another example was when the boys were acting like idiots, and Justin was made to look like a brat for not joining in. Maybe he just has some maturity and doesn't want to act like a 12 year old. (Luke is not a bad person but he is very easily influenced by Shane & Dermott. Justin, for better or worse, is his own person).