That's not how the line goes. It's two sentences: "Mages cannot be treated like people. They are not like you and me." There's no way to escape the depersonalizing intent of the first sentence.
Let's put this into perspective.
When I was 8, I was mauled by a german shepherd. It was brutal and horrifying. For years after, I hated all large dogs. To me, they were all dangerous. They were monsters, not pets. The breed didn't matter (though obviously my anxiety pitched when I was around shepherds), a large dog could hurt me just like that last one did. I loved dogs. I had a sheltie and a maltese back then, and never hated them. They hadn't hurt me.
Was I a bad person back then, this injured kid with a new-found phobia? Am I now?
Of course not. It would be silly to call me a bad person because I was scared of these monstrous big dogs who, quite frankly, could have killed me.
Just because we're talking about people here (the mages), it doesn't mean that it isn't natural -- or acceptable -- to develop a fear that looks a lot like hate. That's how I view Cullen and his feelings towards mages then. He could have been killed. He had ever right to be wary or, dare I say it, hateful.
Just... think about that.
I agree.
People forget, or just choose to ignore, the fact that Cullen is still suffering PTSD only a YEAR after his torture. A small vacation isn't going to fix him. Soldiers can go through the same thing; I read an article about a soldier who was caught, tortured, but eventually rescued. His views on the native people HE WAS PROTECTING scewed terribly because of that experience.
PTSD doesn't just go away, and I imagine the sort of healthcare he needs just isn't available aside from confiding in someone he trusts...and his fears and anger could easily be twisted in the wrong hands. His development, especially in Act 3 on the Templar route, proves he still holds to his ideal about the Order. It would have been much much MUCH easier to just kill all the mages and follow his superior. Instead, he chose to otherwise.
Cullen's strength and willingness to see past his own demons is why I like and respect him so much.
Word.
Ok first attempt:

OMG IT WORKED. Thank you for the Cullen welcomes!!
Btw, this is my favorite reaction gif ever. I use it thoroughly. 