@gluvnast doesn't understand the difference between Cap knowing that Bucky killed Tony's parents, and Cap knowing there existed footage of this. Cap might not have known that a tape existed but he had known since The Winter Soldier that Hydra was behind the death of Tony's parents. After Cap and Falcon get a hold of Bucky, Cap asks him what Zemo wanted to know, which were the details of his mission killing Tony's parents. If you can't fill in the gaps from there (Bucky tells Cap and thus Cap knows), then sorry breh, you might wanna stick to watching Christopher Nolan movies were every plot detail is being explained to you in a five minute speech.
Even though I forgotten the scene where Rogers learned that Tony's father's death wasn't an accident..... if he would of assumed it was from HYDRA... then it would of been more of a reason to TELL HIM. I understood slightly because it knew explicitly that it was Bucky... but even with that, knowing how Rogers when it comes to telling the truth, and having honor and duty that he would of long told Tony about it and explained why. The fact that he didn't and they used this at the end to force one final battle rubbed me the wrong way... This should of been AT LEAST something that be the catalyst of the entire film.
It was poorly written.