Still can't wait to hear him justify "Mages aren't people [like you and me]." though, especially if Hawke was a mage; Varric could've heard him say it. I feel it will be relevant whether or not the Inquisitor is a mage, because I imagine he'll have to work closely enough with Vivienne.
To be fair, they aren't. Only mages can do all the cool magic spells. Normal humans can't, so he's right they aren't like "you and me". Plus, it's barely been a year since his torture by that point, so of course he's going to be angry and still suffering.
Also, I wish people would stop using that one line to justify him being the "bad guy", I think by now it's pretty clear that he isn't given that he's part of the Inquisition leading your troops, not to mention both his writer and David Gaider telling us he isn't bad/evil. If he had wanted to slay mages then he would have rebelled with the others. He didn't. That speaks volumes.
Rant over.