GW Facebook wrote:
Games Workshop owns and protects many valuable trademarks in a number of territories and classes across the world. For example, 'Warhammer' and 'Space Marine' are registered trademarks in a number of classes and territories. In some other territories and classes they are unregistered trademarks protected by commercial use. Whenever we are informed of, or otherwise discover, a commercially available product whose title is or uses a Games Workshop trademark without our consent, we have no choice but to take reasonable action. We would be failing in our duty to our shareholders if we did not protect our property.
To be clear, Games Workshop has never claimed to own words or phrases such as 'warhammer' or 'space marine' as regards their general use in everyday life, for example within a body of prose. By illustration, although Games Workshop clearly owns many registered trademarks for the Warhammer brand, we do not claim to own the word 'warhammer' in common use as a hand weapon.
Trademarks as opposed to use of a word in prose or everyday language are two very different things. Games Workshop is always vigilant in protecting the former, but never makes any claim to owning the latter.
GW actually responding to criticism...