How about concentrating on the positive things Satan has done ... and forget the negatives? How would THAT sit with you? Definitely, there ARE a few positive things Satan has to do ... in order to con people to get them to follow him.
This idea of forgetting about all the Christian atrocities committed throughout history in the name of Jesus and focusing only on the POSITIVE ... is a major cop-out. Why is it a cop-out? Because it keeps people from facing the truth and dealing with truth. It keeps people in a deceptive state of mind.
If I were to see Christians saying, "yes we DID all of those things and they were WRONG -(with no "buts" for excuses)- and NOW we are going to do something DIFFERENT ..."
...I might regain some confidence in the Christian "way."
But that won't happen and you know why not? Because if Christians ever did that and then re-evaluated what they could actually salvage from the faith based on pure honesty ...
... they'd discover that there's nothing particularly valuable left in that ancient religion that couldn't be better done by upgrading to something current.