"As did I. You are the right height for one, if not as stocky." That aside: "The relationship between magic, dreaming, and the Fade is complicated. As Solas will spend hours telling you. But take away one of the three and you lose the other two, to some degree." And take away they did, amongst the Circles. Lavellan can never imagine facing down the choice to lose her magic, her emotions, and her dreams if she felt she couldn't survive temptation by demons; she's grateful for never having to have made that choice.

But she feels as if that's clear enough for the moment. Dwarves cannot access the Fade, therefore they cannot access magic and cannot dream. They cannot dream, so they cannot be mages and can't access the Fade. They cannot be mages, and therefore will never dream, never experience the Fade.