A lot more in common... like a lack of diversity? Because Seattle, last I checked, is far more white, wealthy, and single-family than many of the outlying suburbs where many of its police officers actually live. Diversity doesn't dictate values, but if it's "racial non-discrimination" you're looking for, maybe one of the whitest cities in the country isn't the one to emulate.
Not to mention the fact that---as I noted yesterday---many cops have reasons other than failing to share "Seattle's values" to live outside the city, including affordability and the fact that they're uncomfortable living cheek-to-jowl with people they've arrested. Moreover, giving preferential treatment to police candidates who live in Seattle doesn't just veer into Big Brother territory (should newspaper reporters, or any other underpaid workers, have to live, company-town-style, inside the cities they cover?), it also may be against state law to make them do so.