I had a similar experience…
The same thing happened to me in Berlin in 2010 while attending the founding of the Die Freiheit’s political party (now defunct). I inquired from the journo who was standing outside the building why was he there? Who or what was he covering?
He stated that it was about the Dutch ‘racist’ (Geert Wilders) coming to give a speech. He then got all uptight because I was filming him.