did u not read this?

"People squealed as they hurled balls of snow across the largely deserted road. Then, a snowball or two slammed into a Hummer. The driver, a plainclothes detective whom D.C. police refused to identify, got out, drew his gun and exchanged angry words with revelers, according to video footage and witnesses."

the road barely had traffic and they had people on each side of the road that they were throwing the snowballs at. hence the phrase "snowball fight"

and as for the protection part, nobody intended to hurt him, as he never even INDENTIFIED himself

"Then a maroon Hummer pulled up and was hit by snowballs. A man in plainclothes got out with a gun in his left hand."