I've lived in the southern USA almost my whole life. I am accustomed to racism, unfortunately, but Asian racism hits different. It's wild.

It seems to me that racism is an easy thing for any human to fall into if they are not conditioned out of that from an early age by their family and by their social environment. Fear and hatred of others not like ourselves seems like it could be potentially be a "default" and may have even been an advantage early on when everyone outside your tribe was seen as an enemy. I haven't read anything about this but is just my impression. Also, you'd be surprised by how racist many countries and cultures are, especially those that are very racially homogeneous and that have less contact with people of other races.