I doubt it's your name/ethnicity. It's probably more that you're over qualified and they're afraid you're going to work for 3 months before getting a better job better matching your qualifications. To be clear they shouldn't discriminate because of over qualifications either.
I say this as someone who works in the public sector, for many years. Every year I have to go to an EEO training and they drill it home what we can and can't consider. There's no way they are managing to discriminate against white sounding names for a decade without someone blowing the whistle. I 100% guarantee some fox news watcher there is blowing the whistle for their 20 minutes of fame.