You make a good point but we cannot decide all matters of government and law based upon the competitive nature of societies alone. But if we do ask the question - Does excluding ex-cons from voting strengthen or weaken a society overall? It is arguable of course but I would argue it doesn't- the benefit of including all citizens in the vote rather than excluding some of its most disadvantaged and alienated, would surely be greater than the cost. The weighting of ex-cons in the vote result is unlikely to be significant whereas the cost of continuing to disadvantage and ostracise them is probably going to be greater. Slightly obtuse but 'SAS Rogue Heroes' might be a relevant reference...at least decent entertainment.