I've seen it done wrong, where a little kid is scared, for example. Telling him to man up might just provoke an internal storm instead of encouraging him. Acknowledging the fear and walking him through it, so that he comes out on the other side, can give him the calm and self-control to get through a scary movie or stitches.

But the people pushing a simple parental mistake (which is temporary with a loving parent) as toxic, don't usually have the best interests of the child in mind.