I too have seen this many times over the past 5 years, but I feel that is a family issue. If the mom lets it happen, she is just a bad.
My son has be lucky enough to experience many wins and only a few loses over the past 5 years, but even after the losses, his dad tells him what he did right not wrong. Don't get me wrong, after our son has gotten over the loss, he will then point out what he did wrong!!