A reader writes:
I grew up in Portland, and my initial thought when seeing the map was that Oregon is very independent and libertarian. We don't care about societal pressures or what our neighbors might think. We're going to do what makes us happy and what we think might be fun. And if that includes gay sex, then so be it.
But then my second thought was, "In reality, it's probably because there's lots of lesbians in Oregon."
Another:
I think the answer to your question "What's up with Oregon?" could be answered in one word: Portland. For whatever reason, it seems to be extremely sexually adventurous town. Bisexuality and open relationships don't even raise our eyebrows. Polyamory even edges into the discussion from time to time.
I wish I had some stats on why, but I can only go on my experience. I'm a (99%) straight male that's done more than my fair share of dating and I can't think of a single solidly straight woman I've ever dated here. I've even dated lesbians. How is that possible? You'd have to allow them to explain the complexities of their sexuality because I never got that one myself.
Point is, things that don't fly elsewhere in the country seem to be normal in our little bubble. Also, the percentage of young residents who use OK Cupid in places like Portland is probably much higher than Alabama, the bluest on the OK Cupid map. People tend to settle down early in those parts. The people who escape the South and Midwest (like myself) flee to the coasts - places where being liberal minded about politics, sexuality, and oh, you know, recycling a can, aren't viewed with hostility by their neighbors.
According to a list of the most lesbian-friendly cities, "If Northampton is Lesbianville of the East, Portland is Lesbianville of the West." Guide here.