Should we judge history by historic standards, or modern standards?

Historicism vs Presentism

I would argue that historicism is the right choice here. Standards change as society evolves

If someone still abides by a certain thing as in Religion then today's standards.

If someone is simply trying to find out whether or not x person was good in their time then by their standards. 

There are more examples but I guess these would be the most common. 

Are you claiming morality changes?

What's the difference between historic standards and modern standards?

Eg. What today is generally regarded as Paedophilia, probably used to be accepted as the norm at one time.

Though what is the point of judging history anyway. Even if a judgement is made, history can't be changed.

Unless we are talking about re-judging those still living of course.

Stoning women to death for fucking.