JD Vance was the object of their booing.
I think it was necessary to continue to show Mr Trump that he is despised by a huge number of people worldwide.
What I.C.E. being there shows me that the Italian government are okay with what Mr Trump and I.C.E. are doing.
Otherwise it was quite within their power to not grant visas to the agents.
A condition of entry to Italy is that everyone is fingerprinted and have their faces photographed. I wonder if this was instigated with the I.C.E. agents.