man not even close HN is so cruel

It is not cruel, it is a hypothetical question/ethical dilemma just like the https://en.wikipedia.org/wiki/Trolley_problem

If you could go back in time would you kill Hitler or silently give him neuroblastoma at an age before he announced his evil ideas so that he doesn't become a martyr?

Check out: https://www.imdb.com/title/tt0734776/