Berdiche Axemen are the worst of the lot.. They won't attack against cavalry or infantry. They do a little damage on the charge and then stand there. A unit of peasant archers can kill them in a protracted battle because they just sit there and don't fight back.

Also, it's got nothing to do with the skeleton compensation value... You can change that and it does nothing. It's due to a bug in their actual animation set which is laid out in descr_skeleton.txt