Unfortunately, the tag "washington" has been embraced by three groups: people interested in the surname, people interested in the state, and people interested in the city of Washington, DC). Because surnames are the default purpose of tags, that usage is something that isn't going to change.
If people engaged with the places could agree on new G2G tags to use for the places (maybe washington_state and washington_dc) and would agree to publicize the decision to other WikiTreers, I expect that those of us in the Moderators Project could help with retagging of older posts.