We are currently investigating issues some players are having logging into the European PC/Mac megaserver. We will update as new information becomes available.
I suspect the real answer is because NPC wolves and undead have a specific flag associated with them, which awards Guild XP on death. I suppose it's possible their Fighter's Guild XP payouts are hand coded. Either way, players simply don't, "count," because they don't meet the prereqs for some reason.