Target For Racism Already

So we went to pick Chloe up from her After School program today and she complained that she had a bad day. We asked why? she said one of her classmate – a boy said to her – that he hates CHINESE! *slap forehead*. We asked Chloe if she had spoken to her teacher about it – and she said yes – and that her teacher had spoken to her entire class about it. I don’t know how a 7 yrs old would said something like that to another kid in his class. In our household, we never use the word “HATE” – according to Chloe “HATE” itself is already a bad word. While we constantly teach Chloe right from wrong – why are other kids saying hurtful things to my daughter? What had that kid been taught at home or around home/friends? I’m curious to know exactly what is going on at this boy’s home/friends. Should I be worried for Chloe? or should i just brush it off as a kid’s thing – that they don’t know any better?