I guess if he admits that he is here illegally, he could say that he is honest in all his dealings with his fellow man, but that wouldn't mean that he was perfect, any more than if I say that I am honest in all my dealings with my fellow man but regularly break the speed limit.
The comparison is non-existent. How can he say he is honest in all his dealings if he is illegally in the country and how can the man who regularly break the speed limit say the same thing?
Are you talking a moral of their own?