Probably in the minority here, but I’m positive there’s no way Steve could’ve known with absolute, concrete certainty that Bucky was the one who killed Tony’s parents, prior to Zemo’s reveal.
All he saw was a photo of the headline of Howard’s death included in Zola’s footage. So he knew HYDRA was responsible for the deaths, but I think he was being honest when he told Tony “I didn’t know it was him.” Then he caved and just said “yes” because Tony emphasized “did you know” as in “did you know it wasn’t just an ordinary car accident?”
Steve probably pieced together the likelihood that it was Bucky who did it, but wanted to believe it wasn’t true, that HYDRA had sent someone else to do it. Which explains why he didn’t tell Tony. He had no proof it was true. And he didn’t want it to be true anyway. Why should he say “I think my best friend might’ve killed your parents but it’s just a hunch?” Why would ANYONE want to say that to their friend?
Steve Rogers deserves no hate.
