But the problem isn't stated so, it's not symmetrical, it's about "ruining his evening", which a lost opportunity to add $40 to my net worth won't cause for me.
I disagree with you on how the problem was stated -- "ruining his evening" isn't the only effect. You also get 40 dollars.
But even with a rephrasing that'd use the words "burning Hitler's wallet' instead (so that there's no benefit of 40 dollars for me) I might value satisfying my sadistic desire to ruin Hitler's evening more than I valued Hitler keeping his 40 dollars. Or not -- it depends how much I tolerated sadism against evil dictators in myself.
That doesn't mean I would kill Hitler for the emotional satisfaction (always assuming there's no measurable difference one way or another to future horrors): I value human life (even Hitler's life) more than I value my brief personal emotional satisfaction at having vengeance done.
Here's an edited version of a puzzle from the book "Chuck Klosterman four" by Chuck Klosterman.
When should you punish someone for a crime they will commit in the future? Discuss.