"Grindelwald's behavior made sense to him at the time, and you can kind of understand how he got the ideas he did"? Sure! "Grindelwald was just a big soppy really"? No!

That's exactly it. I understand what you mean about sympathizing with villains, and I agree that it's really interesting to analyze their motives. (Although I prefer the morally ambiguous, Ravenclaw-gone-wrong kind - hi, Fëanor!) What confuses me is when people go from explaining/analyzing to *justifying* them... and then I start to back away slowly, thanks.