Jews must travel with a posse in such places. It’s just commonsense.
Although the remarks to the rabbi were insulting and that kind antisemitic hate speech may well be a crime in Austria, I honestly don't know if you are overreacting. Depends on the frequency of this kind of stuff and if these incidents frequently escalate into violence.
My guess is that the perps might have been thinking of violence but that the sight of the police deterred them.