> Is he an EU citizen?

Based on his biography (hasbrouck.org/bio/whoami.html) I believe he is an American citizen. I see records about him being born in the USA and nothing about any moves to a European country (other than his world travels for activism and other short-term purposes). If he were a European citizen, I'd expect his complaints to be directed at his local DPA rather than at DT/T-Mobile directly.

I'm no lawyer so I'm not sure how legally binding his communication with T-Mobile/DT about the exact use of his data really is.