[@Kirah]

Well, David's best friend is a Ravenclaw muggleborn. He really judges people more on their intelligence and creativity rather than anything else. A rationalist of sorts.

So... he is biased against the sort of person that would end up in Gryffindor, but not against muggleborns. Hell, he isn't even entirely human, those elfy ears of his are bound to get some pokes down in Slytherin ^^.