It’s more likely that he wanted to allow players, who are bench warmers, a chance to perform. It was likely a game that wouldn’t affect his statistics much, which allows him to take better players out and put in lesser players.
In todays education system, if a coach doesn’t play everybody sometime during the season, it can cost him his job.
Unless there is more information than you have presented, that’s probably all it was.
Some people find that "motivating". Me? If I am performing well and I know it, that crap is a definite indicator that it is time to move on.