To me De Blasio had the temerity to attend knowing full well what would happen, even after he was dis-invited to the funeral.
I doubt he was dis-invited. The policemen’s unions made it clear they didn’t want him there, but the families didn’t dis-invite him. It’s standard protocol for the mayor to attend the wake/funeral of a policeman/fireman killed in the line of duty. It would take the family’s actively asking him not to attend, and that just didn’t happen. The unions or the dozens/hundreds/thousands of NYPD don’t make that call.