Lucke, Petry, Gauland, Adam (the Afd founders) are no ordinary conservative-liberal politicians.
Lucke is indeed not an ordinary politician, because he is not a politician anymore at all. He is a professor of economics, a civil servant with the right and obligation to lecture. And it's the obligation of his employer (i.e. the state of Hamburg) to make sure he can do that. Case closed.
The funniest part of it all is then that the resident Pluralos of course also supported the protest, because they consider him a proponent of the evil and ominous "Neoklassik"...