Father Giles takes the death of Crystal's brother-in-law hardest of any of the other drivers in rehab. The show presents this as remorsefulness for his own failures to yield in the past, but it takes a new turn when you realise that Giles also owns a motor scooter, and could have been at risk to a similar accident.
There is no obligation to show up to one of these shows. This means all the people that appear on the show are there of their own volition. They are also all licensed and insured people. This means that, as bad as they are, there are people infinitely worse than these people driving around who either didn't qualify (i.e: are driving without insurance or, even worse, no license) or were too ashamed to show up on the show.