Which is why I said, "If they think waterboarding is useful in some situation, let them make that call.", implying that they are smart enough to also judge if it undermines their ability to do their job, leads to misinformation, and puts troops at risk.
You stated pretty succinctly that interrogators asserted all four of your points a, b, c, and d, to which I responded to let them judge all of those and make the decision themselves.