Yeah, but it's not a casual use of the word in Warhammer's IP. Common sense has me agreeing with you that it's a stretch to treat it as if it's some trademark violation. Game studios clearing minor issues like this up seems more likely though. Blizzard certainly isn't going to take this to court and fight it if that is Game Workshop's intention since all they have to do is make a minor adjustment here and there.
Honestly Blizzard could not care less about what this forum thinks about it.