The difference here is most of us would take the shot ourselves if it was Hitler, Stalin or Putin.So we shouldn't speak ill of Hitler? Or Stalin? Or anyone who hasn't generally been a good person when they were alive just because they are dead?
Mind you no one is saying anything ill of Charlie. They just aren't saying anything good about him.
It's one thing to be extremely judgemental of someone you disagree with politically, but you provided a passive justification for his killing.