So there's plenty of history behind the four... five? catchphrases they've been trying to use (and I think they gave up on catchphrasing for now). But for a time they wanted to stop the brain-drain coming from the uppity hipster areas going to SF and friends so they used we don't coast to keep the brains here and the white collar economy strong. Then the all craft beer came and we stayed here so the slogan became history. It wasn't about white dog whistling afaik