Clearly, nothing is absolute. I mean, it can't even be claimed that simulataneous tornados won't throw a cow perfectly towards each other and eventually land through my window a crush me. Sure, the probability is like 99.99999999999999999999999999999999999999999999999 999999999999999999 % that it won't, but nothing is impossible. If you take a statistics/probability class, you will realize this.
I understand statistics and probability just fine. I need to slow my reading down a bit though, I skimmed over the word possibly.
Back to the debate, I see both of your points on willpower but the fact is there is always reasonable doubt. Lying is simple, and most murders lie their asses off in court trying to get out of their punishment. Doesn't this show something wrong? They don't have the willpower to contain what they were feeling and can get off the hook because they claimed they changed? It's bullshit. I'll equate it to Zelaron, do you want The1 coming back and annoying you all? No, of course not, and he claimed to have changed. It's the same principle, although The1 and a violent killer aren't the same obviously.