No, Seattle is Not the New San Francisco
David Sasaki

“The city is becoming more diverse” statement links to an Urban Institute map and race and age demographic projections of a western WA region far outside the Seattle city and County boundaries. From 2000–2010 Seattle racial diversity actually grew at a slower pace compared to King County as a whole and the US:

This trend would seem to suggest that while the city is generally following national trends of more “non-whites”, it is becoming less racially diverse than both the surrounding area and the country as a whole.