But that's not what you said...
You said, "When people's lives are at stake, if you aren't 100% sure, then you don't act."
In war, you'll never be 100% certain about an attack. Even with technology beyond a Prussian's general's wildest fantasy, we still don't have 100% certainty. Odds are, we never will. So, either we go by what you said and be totally hamstrung or we have to make decisions on admittedly imperfect data. Obviously, we have to do the latter.