It is nice to see that even the state of WA thinks what the city of Seattle is trying to is illegal. I doubt they too will jump on the public band wagon of a law suit, but if it does go to WA Supreme court, hopefully the state will side on their own laws.
As a none Seattle, and King County resident, I often take an attitude of "let the idiots in Seattle do what they want, I will go elsewhere" but even laws like this can set a bad precedent for rest of us in WA. It is very good to see action taken against this.