In any event, "small subset" vs. "large market" are the parent's words. And, yes, of course a product that is aimed at a small subset of the market is the opposite of a product that is aimed at a large market. So, it contradicts, as you say.
These are relative terms that speak to the size of the market being addressed, so by definition small vs. large are opposites.
Perhaps the parent meant to say a "small, but profitable market".