Did you actually peruse the site you offered? http://www.churchbcc.org/ I clicked on several links. One link connected me to an article on World Vision (that just had to change its course on same sex marriage because of what would be a financial fallout.) Click on the associated links. The church seems to be more about saving people out of poverty than the Gospel and Jesus dying on the Cross, shedding His Blood to save us from our sins. We should all be about helping people in poverty. Maybe you have a different definition of liberal church.
You've got to realize this is Seattle and the definition of liberal has to be somewhat relative. It is not a liberal church compared to 90% of its neighbors (both churches and people).
In more absolute terms, almost all churches in Seattle are liberal from my perspective. For example, there are only three traditional Catholic parishes in the greater Seattle area (two diocese and one independent). Possibly an eastern Catholic or two as well. The others are liberal modernist parishes.