This was not going nearly the way Tony had expected. Pietro wasn't really defending himself or explaining his actions or giving Tony any reason to understand; not the vaguest sketch of reason or path of logic or direction Tony could even approach this from, identify the problem and fix it. He was just talking, like someone was whispering in his ear, like he expected everyone to just be friends and understand and accept each other's impulses to dominate an entire people through violence and terror. Tony was supposed to hug it out and think of it as some characteristic tic that people who really loved each other could overlook.
Unfortunately for Pietro, Tony just happened to think that sort of person could get fucked. And, good God, did he want to help Pietro, because he knew he was just brainwashed and conditioned to those beliefs and this dependence and fear of his father since he was an infant, but if Tony was going to get hurt in the process he really didn't need to be Pietro's friend to do it. "Don't you dare--" he started to say, putting his own distance between them and holding up a hand for Pietro to just stop speaking, stop thinking he had the prerogative to even act like he cared about either of them. Tony's fingers curled into a fist, hand still between them, and he bit his lip until he had quelled that wave of frustration.
Of course what Pietro felt strongest about put everyone on edge. If he went too far, this was the person he was going to become. They didn't get mad enough at him to keep this from happening. Tony learned that lesson thoroughly for himself, except he was always right and knew enough to keep it to himself to cut out the conflict. He couldn't count the number of times Steve had ended up explosively angry at him for not admitting his plans.
His fingers fanned, not quite welcoming Pietro to speak again, but determining the moment passed and the time to just try to move on. Tony had decided he couldn't do this anymore. He had no words of comfort for Wanda. He had no excuse to bring to the Avengers. He had less than he started with, just a knot of frustration twisting in his back. His hand dropped and he nodded with finality, not meeting Pietro's eye anymore, and turned to the solitude of the beach. He needed to be away from this.