I think its possible for a coach to get out of sorts with players for various reasons. I've seen it happen when the player doesn't acknowledge the coach as the supreme source of information about the sport.
Some coaches develop the idea that their job is to teach a particular kid a lesson. Sometimes this is necessary. Sometimes its not good for the kid or the team.
I'd take a cue from the coach's long term record at attracting and developing players. If he's constantly competitive, you should give him the benefit of the doubt. If he's an excuse-maker who privately complains that he doesn't get the good athletes, or that his kids don't want to work hard, then you might be onto something with your concerns. Those guys actually can't stand it when they have anyone who is better than they were. In any case, there is probably very little you can do about it, so its critical to cope as best you can.
Telling the kids how good they're not, or worse, how bad they are is not the formula for a strong program.