Coup (d'état) is a loaded expression that immediately alienates at least half of the voters because it "seems" a little over the top. Those of us who have been following Mueller's antics the past couple of years can see it, but most people see it as just another Watergate that led to a President's resignation.
I'm torn between calling this spade a spade, or soft-pedaling the charge in order to get more people on board.