I really don't think they should let the other sort in, do you? They're just not the same, they've never been brought up to know our ways. Some of them have never even heard of Hogwarts until they get the letter, I imagine. I think they should keep it in the old wizarding families. What's your surname, anyway? (5.184)
Here, Malfoy sets up a connection between family and class. The "old wizarding families" are, to him, a higher class than the "other sort," who haven't been brought up to learn magic. Ironically, even though Harry can be thought of as practically wizarding royalty, he's in the same ignorant position as many mixed-blood wizards, and he is himself only one-generation pureblood.