That they endorsed them in the first place seeing the treatment towards law enforcement...
Politics and money. Unions will endorse anyone in position to help the union (bosses).
The Democrats however stepped over a line that even corrupt union bosses could not tolerate (de-funding the police).
This had nothing to do with the effigy, that was just the excuse they needed.
Hope that’s the case. I suspect that scores of individual law enforcement across country will just vote accordingly.