The world is more nuanced and complicated than boxing everything into the two major ideologies of Republican and Democrat. Unfortunately the nature of our political system these days makes it hard for the majority of us who fall between this dichotomy to speak and be heard.
I registered as a Libertarian when I first arrived in Portland but got out of it due to some some weird internal party issues and divides.
I registered as a Democrat to vote for Bernie Sanders during the closed primaries because I wanted to have his voice debating a traditional conservative and have a major discussion regarding the Left vs Right. And frankly, by the time the primaries get to Oregon registered republicans , and usually democrats, don’t have a voice as the winner of the primaries is often determined by that point.