Because he didn't want his chances of getting hired drop in 1/10th what they were...
>but if I Google somebody or something comes up in a background check that's going to do more damage than if they'd just been up-front about it.
Well, then that's the same attitude as the one that doesn't give them the job in the first place. What business is of yours, their employee, if they did jail time in their past, as long as they are good at their job? Why should they volunteer that information to you, not only since giving it such kills their chances in lots of other employees, but in principle too?