I don’t believe pointing out a case where certainty is ensured missed the point; rather, it argues the point. He’s giving an example where execution would be okay due to their being absolute certainty, not arguing that it should be the same outcome where there isn’t absolute certainty.
That is a false dichotomy. If you accept the idea of the existence of cases with certainty there is the possibility of the restriction of the use of the death penalty to those cases.
That is not the false dichotomy you proposed, you just moved the goal posts to make it an actual dichotomy.
Indeed. And he was charged for that.