American TKD is pathetic. I'm not supprised by that at all. The TKD blackbelt going down is a cliche.
the trouble is that most of them are skinny geeks to begin with. Their art isn't that realistic and gives them the huge self esteem boost because they believe they can defend themselves.
I'm not that high in my art and the slightest knowlege of leg wrestling or infighting, is usually more than they can handle....if you have a few good angles and get to their back gate, they are done.