You raise a very interesting point. I think the position of the John Howard Society is that people who have paid into the scheme should stand as equals to one another. If someone else has done something that disentitles them to get to work or incapacitates them to get to work, whether by their choice or not by their choice, then they should stand equal to the offender who has committed an offence.
I can guarantee you that he would prefer being at work to being behind bars, so his decision, his volition, is not connected to not wanting to be at work. It's not squarely connected with the basis for employment or employment insurance.