It's because Portland is full of hipsters.  Portland and the surrounding area is also host to a ton of different colleges and universities.  Hipsters tend to be SJW, as do a large portion of students, due to the way the SJW have basically taken over many campuses inside and outside of the classroom.  Many of the faculty are either sympathetic or active supporters.  FA has pretty much hitched onto the SJW wagon by clothing itself in much the same rhetoric, so it makes sense that it would be so rife in a place like Portland. Portland is basically the San Fransisco of Oregon.