Jonathan, someone who works directly with the forces he controls, is most aware of right and wrong. Andrew summons the magic he deals with, and he's wishy-washy and well, takes on the personality of those he spends time with. And Warren didn't understand or appreciate the powers that he was working with, and he was the one working the furthest away from what we might call 'true' magic (like the sort Giles 'infected' Willow with).
Re: It actually works very well in terms of the moral coding of the Trio
Jonathan, someone who works directly with the forces he controls, is most aware of right and wrong. Andrew summons the magic he deals with, and he's wishy-washy and well, takes on the personality of those he spends time with. And Warren didn't understand or appreciate the powers that he was working with, and he was the one working the furthest away from what we might call 'true' magic (like the sort Giles 'infected' Willow with).
Very cool.