First off Dany is a mass murderer that killed thousands of civilians and surrendered troops and she did it in less than 30 minutes. That is why she was killed. It was justice. She is no more a victim than Nazis that were executed for their war crimes.
Jon on the other hand is in fact a victim. He loved Dany, he believed in her, he risked himself and his people and family for her. And she betrayed him. She made him an accomplice in mass murder on a scale unseen in Westerosi history. She then tried to frame her heinous actions as liberation. But even after that he still loved her and wanted to believe she could turn back from her bloodlust, and he gave her a chance, and she made it clear she wouldnt turn back. For her crimes and to stop further brutality he executed her. Rather than just setting aside her actions to be with her he did what was needed and what was right. He chose the people and Westeros over the woman he loved. So yeah, he IS a victim regardless of the fact he has a penis.
Edit: It could be argued that Dany is a victim of circumstance, the choices of people around her, and her own mistakes, and I can certainly agree in that regard that she is a victim, but she isnt a victim for Jon executing her. When you do something like Dany did you dont get to play the victim card when someone kills you for it.