That isn't the way the world - or most morality systems - work.

A surgeon who saves a thousand lives doesn't get a pass for the one murder they commit.

If the person who eventually cures cancer also happens to be a rapist, do you remember their name with awe or pity?

The sort of Felicific Calculus practiced by the "Effective" Altruists is a tawdry trick designed to excuse despicable behaviour.