It's Seattle, so the vast majority of students are very liberal/progressive. This means that the students are accepting of racial minorities (for the most part--there is still some progress to be made), those of the LGBTQ community, and different economic backgrounds. However, it also means that if you have slightly different political beliefs, you will not be accepted. It's a closed-minded community in this particular way. In discussion-based core classes, you will be treated very differently if you express an opinion that is not in line with Seattle's very rigid belief system, and professors usually do very little to create an atmosphere where different opinions can openly be discussed. I've also noticed some covert discrimination against religious students, even though it's a religious school.
That's pretty much how Seattle is in general with regard to diversity of beliefs: Very accepting but only when it's convenient.