If joews are white...

Then why is it considered racist to discriminate against Jews, if they aren't a different race?

If you discriminate/hate on another white guy, you're just a douchebag.
But if you discriminate/hate on a Jewish person, you're a racist and anti-Semite.

The Jews of Europe, aka Ashkenazi Jews are actually Khazars who are originate from north-west Kazakhstan. Khazars are a Turkic ethnic group, thus making them closely related to Kazakhs, Turks, Uzbeks, Turkmen, Tatars, Azeris etc.