What constitute discrimination?

A member in this organization contacted me and inquired about my ethnicity made up. After I mentioned part "Chinese", he threw out the term "anchor baby".

Without asking more background details, he spew out anchor baby. Regardless of his ignorance, but the fact that he threw the term, he was plain prejudice in my honest opinion.

Anchor baby means or a term used to refer to a child born to a noncitizen mother in a country which has birthright citizenship, especially when viewed as providing an advantage to family members seeking to secure citizenship or legal residency.

So what constitutes discriminatory acts? Is calling someone anchor baby without full investigation of background, discriminatory?