Zemo's successfully split the Avengers apart, but his revenge still isn't finished. He's broken Tony, now it's his turn to destroy Steve, and he does it by striking Steve's weak spot and getting at Bucky. He sends a video to Steve of himself using special trigger words on Bucky and raping him, all the while degrading him, and making Bucky praise and worship him and acting like he enjoys Zemo's abuse of him, and talking about how his cock feels much better than Steve's ever did.