That Cap Poster end blurb "If you want to learn more..Ask someone you trust". So don't ask your tipsy drunken parents, how about that stranger outside offering you some candy?
I do appreciate Cap's concern and if he were a real guy and I had drunk parents I might ask him about it because he would be someone I'd trust. But first I would ask him why when he had the chance he didn't kill Hitler instead of just slugging him?
I think you can give him a break on this occasion on account of everything else he's dealing with in this moment. That he even has time to take a swing at Hitler while being shot at by four men is pretty impressive. Besides, covers are generally expected to be more symbolic than literal.
The above is from Captain America Comics #2 and illustrates how despite the Captain America appearing on the covers of his books as a fearsome figure who'll stop at nothing to exact the world's revenge against Hitler, the stories within those comics presented a prankster Cap who seemed far more content to tweak Hitler's nose or pop out of canons with a 'Nyyyahhh, what's up, Doc?" attitude. Note the "GERMANS FIND HITLER AND GOERRING IN ASHCAN" headline in the third last panel.
The Captain America taught in schools
The Captain America you don't hear about in history books