When it come to Hitler people will generally approve of political assassinations and infanticide if it would have meant that Hitler were killed before world war 2. Any benefit that society would have gain if those methods would had been established as the norm would however be dwarfed from the negatives. Sometimes bad methods make things initially better, but long term has terrible consequences.

As a minor historical perspective. The French Revolution is know in Europe as one of the bloodiest period in France under the name of Reign of Terror, and ended with Napoleon who then initiated the Napoleonic Wars, which is also know as one of the biggest war in Europe.