> I’m confused. I usually like to cruise control in the middle lane (at around 3-5 over the speed limit); how does this cause problems for you?
If it were one car, it would be a minor annoyance, at worst. But this style of driving is really popular, so it's a steady line of cars cruising the middle lane in a line. It divides the freeway into two one lane roads, bottlenecking traffic and making it difficult for people who are in the left lane to get to the right in order to take their exit.
It may be that the dynamics are different in your area. Between Portland and Salem, Oregon, the exits are several miles apart so there's not much merging traffic.
> What would you propose I do differently?
In my experience the best freeway experience is when people pass only on the left, and there is enough of a speed differential between lanes that when you need to change lanes you can always find a spot you fit in. It gets aggravating when traffic is pacing, especially at high speeds, because it makes it a lot tougher to make comfortable lane movements. It's worse when the left lane is filled with cruisers, because they always bunch up and follow each other with a 1-second separation, making lane switching hard (and when you turn your signal on, at least half of them will just speed up to make sure the gap is even tighter).
I'm not going to tell you how I think you should drive. There are a lot of factors that are not necessarily the same between where I drive and where you drive. But I can tell you that the dynamics on this section of I-5 up here are just awful. It's a well known local phenomenon, everyone I've ever ridden with through that section of I-5 comments on how terrible the traffic gets with passing on the right, left, and locked up down the center.