To quote Wikipedia, it's apparently supposed to refer to "Eurpoeans perceived to be particularly stylish and affluent socialites. It is often used ironically or self-referentially, and is not meant to be the European equivalent of the typical American derogatory term 'white trash'."
So, to answer your question, it apparently is not targeting a race or ethnicity per se, but the upper class of European expats living in the US.
Hence, I would argue it is not a racist term, but more of a classist one referring specifically to European "elites", which I assume likely has arisen from both Euroscepticism and (likely) from perceived cultural/behavioral differences between Europe and America.
My 2 cents, take them for what you will, lol.