See but I think the experience of being "mixed" is especially unique and "issue-laden" for those of us who were born into and brought up participating in two or three distinct cultures.
Society will expect such people to adopt an identity affiliated w/a single culture - they will try and fit you neatly into a particular box. And if you come from a bi or multi-cultural family but look racially ambiguous, this kind of thing happens: I had an Italian boyfriend as a teenager and we were madly in love. His mother opened her house to me and we got along just fine. Until. This one day his mother came to my house and met my (Afro-Caribbean) mother for the first time and she got all scared.
Suddenly she was playing match-maker, trying to find her son a new girlfriend. She was quite open about it. Before too long he broke up w/me. We were getting along great but he told me he'd fallen out of love, but I knew that wasn't true because as he said it, he was absolutely sobbing like someone had just killed his favorite pet. If both my parents had looked "mixed" or one was white and one was mixed (as she seemingly expected), that lady might not have been such a thorn in my ass. So I do think it matters what kind of "mixed" you are. Nor is everybody mixed. But yeah, many of us are.