Actually, the quiz does treat Angel as selfish (even though if I were doing it I'd peg him as selfless). You must have misread or misinterpretted what I wrote above--also I mistakenly said that he was treated as non-spiritual, but after checking again I realized that's not true.

Willow: moral, passionate, spiritual, selfish
Angel: moral, dispassionate, spiritual, selfish

So the only difference between Willow and Angel is that he is less passionate. But by passionate in this test they mean "enjoys freetime and the simple things in life"... Angel is too serious and focused on his own goals for that (even though one could easily make the case that passionate can mean the oppositte of what they're using it for here.)