I would argue this is more to do with Portland culture of nice than anything.

I love riding, but I have been run over. No thank you. I will bike for transportation the day we implement Dutch style separated bike lanes (i.e. by an actual physical barrier, even if only a slightly raised bike lane)

Other than that, I drive my mountain bike to areas where there are no cars.

Edit: in the city I'm in now, we just 'created' a bunch of bike lanes. Which means putting paint on a continuous stretch of asphalt and expect vehicles moving at 10mph that weight 50 pounds to do just fine sharing the road with vehicles weighing 2000+ pounds and going 50+ mph. Ridiculous and a waste of my tax dollars.