I think there's more to what happened than just towing a trailer. I'm not saying the driver did or didn't do anything wrong, but aside from everything else, this wasn't a drive down a smooth, paved road. If this incident occurred on pavement, with all conditions within the manufacturer's limits, it would be much easier to fault GM. Either way, it sucks to be the owner of a new, undriveable truck.
It's worth remembering that the Colorado is a modern, light duty truck, just like
so many other makes in the same class. Any frame can be bent, and midsize pickups have the lowest ratings, so which frames are most easily damaged? Maybe there is something inherently wrong with the Colorado's frame, but I won't be surprised if GM is able to defend their position. Modern trucks have many advantages over old ones, but I think there's more strength in the old frames when it comes to towing.