You clearly don’t understand how football (soccer) matches are officiated. The goal for all matches at almost all levels is a three-man system of control with a center referee and two assistant referees. Center referees don’t just stand in the middle of the pitch and often run more distance than many of the players…

Yellow and red cards are shown only to players, substitutes, and substituted players. My quibble is that the center ref didn’t talk to the manager himself and explain that if he doesn’t leave the pitch, the match will be abandoned. I’ve had the same discussion with coaches in youth soccer.