Suzaku's the type of person who refuses to bend or break the rules in any circumstance, ever. That is him in a nutshell. He is the tattletale you knew when you were young who would never let you get into any kind of mischief and wouldn't hesitate to rat you out to whomever the ranking authority was, simply because what you were doing was "wrong" or you had been told "don't do it," regardless of whether or not you could actually get away with whatever you were doing. That is Suzaku in a nutshell, the iron fist of morality personified, with no grey area included.
A character steeped that far in moralfaggotry has no redeeming human qualities, because he sacrifices them for the "higher ideals" he holds to. Lelouch is selfish, has wants and desires, whims, etc. All things that a regular person might have and identify with. Suzaku has none of these, because he walks the straight and narrow and nothing but.
Suzaku is the Lawful Good Paladin of this series. And like every Lawful Good Paladin, NOBODY who isn't a Lawful Good Paladin likes him.
Also fuck you, my mom had a heart of gold, despite her profession.