As to the original question, I think
they are both equally bad but in different ways. Orlais tries to make
itself seem like the moral center of the world, home of the Chantry.
They are really big on culture, fashion and what is proper. But they are
also some of the largest hypocrites on the international stage. They
outlaw slavery, but Leliana tells an elven warden that Orlais is proud
of its elven slaves...sort of, although they don't call them slaves in
order to feel better about themselves. Fiona was an Orlesian sex slave
before she joined the Circle. Her being a sex-slave had nothing to do
with the chantry or the Circle's, but part of Orlais' culture.
Also,
it's highest ranked military order can legally rape commoners, both
human and elven, without reprisal or consequences, and it's considered
to be one of their rights as part of their service to Orlais.
They
also play politics to such a degree that everyone knows of "the game"
and using bards to one-up each other, borderline committing treason, and
nothing is done about it because it's part of the culture.
So Orlais celebrates murder, rape, assassinations, and espionage while all the while pretending it doesn't exist.
Tevinter has blood mages and slavery, and they don't even both denying it. Their atrocities are just as bad, but at least they're honest about it.