Not necessarily. If it's excessive, sure. But depending on the coach and various dynamics with the team, losing it every
now and then can fire people up, strengthen bonds, etc.
I used to have a baseball coach who would get kicked out of games fairly regularly, and it seemed like whenever it happened we played with a little more of a chip on our shoulder for the rest of the game.
Not saying it's always a good thing, but it definitely can be.