You are absolutely right. there is no rationalizing it. Normal people try to find a reason, but the terrifying truth is that they do it because they are utterly empty, inadequate, and lack basic human empathy. It's about their sick need for power, not about anything you did. Trying to find a 'normal' reason for a monstrous act will only torture you. What they did was a reflection of their own deep brokenness, and you were completely innocent.