He doesn't see them as non-people unless you don't become friends with him. He admits he was wrong about that unless he actively hates you.
Even in a playthrough where he and Inquisitor hate each other's guts there are moments where you can see Solas' wall of denial breaking, because no matter of approval level we can still hear banters like this:
Solas: I will remember this. When it is over.
Blackwall: This? This war? The Inquisition?
Solas: The people. How you fought against the tide. It is... courageous.
Iron Bull: Nice job in that last fight, Solas. You really kicked the crap outta that guy.
Solas: I suppose.
Iron Bull: What, you don't think so? You ripped him a new one. It was great!
Solas: Unless the fight is personal, violence is a means to an end. It isn't appropriate to celebrate.
Iron Bull: I don't know. Gotta wonder about anyone who fights as much as we do and doesn't have some fun with it.
Solas: We have fought living men, with loves and families, and all that they might have been is gone.
Iron Bull: Yeah, but they were assholes!
And here's one poignant piece of banter that happens at the end of conversation string with IB that at one point or another became very heated:
Solas: You fought the Tal-Vashoth for a long time, Iron Bull, did you not?
Iron Bull: Every day.
Iron Bull: I'd kill some of them, they'd kill some of my guys, and then I'd kill them some more.
Solas: No man can kill so many people without breaking inside. To survive... those you fight must become monsters.
Iron Bull: The ones that kill innocent people, yeah. The rest... I don't know.
Solas: The mind does marvelous things to protect itself.
When you listen to it you hear that the tone has changed. Solas no longer argues or berates IB for thinking that the Qun is better. He's sympathetic. Understanding. He gets where IB's denial of Tal Vashoth status as anything other than monsters comes from, because... well... he's there, at least on some level. You can hear the admission in his voice.
Thing is that in case Inquisitor doesn't do anything to break his shell, without showing him that they can be champions of people his actions threaten and without someone who can at least nominally understand him Solas never fully shakes away the denial he's in, existing there apparently mostly to help him out carry out his duty.