This has been the true goal all along, and we all knew it. They're just attacking the definition from the other end now as well. Rather than just getting court decisions to redefine marriage and then waiting for society to bring its dictionary up to date, why not force the very definition to change and then wait for the courts to fulfill the definition.
It's a brilliant attack; truly inspired by the spiritual enemy of humankind himself. Imagine Satan's evil chortle as he watches the greatest nation on earth move towards a society-wide sanction of the most heinous perversions. He's been there to see its destructive force in people and nations throughout time, whispering moral equivalence into people's minds. He knows what's in store for such a nation, and he delights at the prospect.