When it comes to trademark, companies are compelled to act. Failing to defend your trademark will make you incapable of defending it in the future. The DMCA can NOT be used for trademark disputes, however. The DMCA exclusively deals with copyright.

Normally, the "interoperability" defense is used to protect instances of circumventing copyright protection mechanisms, not for copying itself. For instance, that was the defense in the case where Lexmark brought a DMCA claim against a third party ink cartridge manufacturer, claiming that by making their ink work, they circumvented protection mechanisms Lexmark claimed existed to protect their copyrighted firmware code in their ink carts. The court didn't buy it, Lexmark lost, it was established that you can do that kind of circumvention. But this copying of the word list... it's different in a couple fundamental ways, and I don't know if there has been a case that has dealt with this sort of thing.