Some media reports have indicated that the uncle wasn't on good terms with the two guys and their immediate family and hadn't spoken to them in 3 years, so his lashing out was predictable. From a few clips of him that were shown on TV, i got the impression that he was over-compensating, most likely in a bid to avoid any vigilante attack on him because of the association.
Virtually every other person-- friends, neighbors, teachers, and an aunt in Toronto-- that these two guys interacted with expressed shock, astonishment, and even denial of what they are alleged to have been involved in. Despite their heinous acts, referring to them as "losers" by the uncle was uncalled for.
In such difficult situations, emotions naturally run wild, and they should be controlled. A person must not lose their civility despite the tragic circumstances. An excellent example was a Boston marathoner that i heard on the radio yesterday.
He had suffered some injuries, but he was much more measured in his criticism of the acts, even acknowledging the loss suffered by the family of the two guys. Now, that's how a person should respond. The uncle needs a lesson in civility.