I think most people are multi-racial or have heritage mixes even though they don't realise it.
That is doubtful. For example, how many people living in countries such as China, Korea, Taiwan, Japan.etc can be considered as multi-racial? (I am taking the entire Mongoloid race as one). India might be mostly multiracial, but can''t say the same about China and the neighboring nations.
And where did the Mongoloids (or people from China, Korea etc) come from? I'm looking at the bigger picture here. It's like when people think being English (or whatever) means something. If you're White English then you've got all sorts of mainland European blood in you. Go back even further and you're African haha.