Then get your hearing checked. He never went into specifics about their pasts, and even if he did, I'm pretty sure Zale had something better in mind for us to do than a bar fight so early in the story.
“…Judge not what a man has done, but judge what he could have done if he was a different bloke altogether. For art thou a leper? And a leper can changeth his spots…” --Rudy Wade, Misfits (Series 4, Episode 8)