Because if there's any criticism one can make of Suzan DelBene, it's that she's too partisan:

Koster and DelBene must rethink their messages. Campaigning on partisan autopilot will not work in the redrawn 1st District.

This is the editorial board, of course, that recently endorsed the losing candidate for governor, attorney general, and secretary of state, not to mention No on the library levy and the fifth place finisher in the 1st District primary. So yeah, both Koster and DelBene should really listen closely to what the Seattle Times says the district's voters want. And then do the opposite.