Well said. The whole point of Captain America used to be his high standards. Captain America stood for inspiration: that's why he carries a shield and not a gun. It's why he could win despite not having superhuman strength. He knew that the real war was for hearts and minds. Once you compromise with torture you have lost the war.
Plus there's the whole thing about torture not really working, and there's no guarantee that the person won't just give the wrong information or the info the person wants to hear rather than the info that they need.
But I think it's just a greater narrative flaw than a moral one. It's just writers who are stuck on this "Torture= bad@$$" thing, that was kind of present during the majority of the 00's, kind of in response to larger political issues in order to take comfort in heroes who real life bad guys would be afraid of, ect, ect. Really, I kind of feel that sort of thing has cycled out and it's no longer as appealing or as comforting as it once was.