Solas' people also understood their responsibility and were willing to die for a common goal. And yet, she lists him sacrificing his people to "buy time for his plans to work" as similar to Mythal killing Compassion. So clearly even when it's a solider that's pledged themselves to your cause, it's still terrible to sacrifice them. Made doubly hypocritical in that the game forces you to do this very thing in the Arbor Wilds - feed your army against Corypheus so that they can clear a path to the temple and buy you time to find whatever's inside. Which means Lavellan's done the very thing she calls out Solas for, especially if she spent the time to do the rituals while her men died against Corypheus.
As for Pride trying to consider her feelings - given that he snapped at her about it already within the chapter, I highly doubt he was just trying to spare her pain. Given how he wilted every time Lavellan made a response, I'm pretty sure we're supposed to see him as "changing" and "seeing the right way," which paints Lavellan as the arbiter of right and wrong in the story, which continues to be extremely grating. Not to mention how it diminishes Pride - everything he thinks or believes is invalid unless Lavellan agrees with it, and she must show him the true path. All take, no give - and frankly, Pride just deserves better than that.
It just goes back to what I brought up the first time - stuff like this just shows a blatant disrespect for the characters, not just for Solas and Pride now, but for Mythal, and really the whole of elven society as well. Mythal was the last scrap of moral nuance the story had. Now it's back to "agree with Lavellan or you're wrong."