Ben genuinely felt guilty. Despite anyone else's assumptions and ideas, he did. James was a different story. Sociopath.
But the fangling was afraid of what sort of punishment was going to be handed down. He didn't kill Leon thankfully. So there was that.
Making eye contact for a few seconds, Ben nodded. "Someone convinced...manipulated me into believing I would be justified in attacking Leon and feeding off of him. I was and still am stupid. I am sorry for attacking Leon. I was wrong to do it. I..it could have been worse. But it's bad enough.."