And even then, the movie basically boiled it down to more along the lines of

Iron Man: Your friend killed my parents?

Captain America: It wasn't his fault, he was brainwashed!

Iron Man: I don't care, let's fight!

(They fight)

Captain America: Let's stop fighting, the real bad guy is getting away!

Iron Man: Okay, I forgive Bucky for killing my parents because I am more mad at Baron Zemo for some reason

Captain America: Good, let us ignore international laws and regulations about our extraordinary renditions

Iron Man: agreed