In case you have not figured it out yet, many bicyclists are also rabid environmentalists. In my case, when I was flipped off, I was travelling East on the McKenzie Pass hiway from Eugene. I wasn't in a town. I was on the open road, well, as open as that road gets before heading up onto the incline. This guy was walking his bike outside the right line - no problem - plenty of room for him and for me to safely pass. I was yet 100 yards away from him when he suddenly stopped... and turned towards me... and stood there flipping me off. He was riding a bike not using fuel. I was guzzling it at about 4 mpg. I think he was one of those environmentalist bikers.
When I was younger up through my college years in the 1960s I biked alot. It was the easiest, quickest, and cheapest way to get around in Corvallis, and especially onto campus to my work and classes. I adopted what I call a survivalist policy. You know how when you happen across a bear in woods, you stop and become very observant and respectful of the bear. On the other hand, if you happen across a coyote, then the coyote stops and becomes respectful of you. I don't want to confront a bear in the woods. The coyote does not want to confront me. Part of having that survivalist mindset is to not provoke bears... nor motorhomes, nor freight trucks, nor trains.
Keep in mind there are also other laws pertaining to the hiways. If you are travelling at a speed of 15 mph or slower under the posted speed, then you must have the vehicle flashers on. Also, if you are travelling slow enough that you are holding up traffic, then you must pull over when safely permitted to allow the buildup of vehicles behind you to pass - this when they amount to five vehicles or more. Those apply to all vehicles on the roads... including bikes. I am sure these roadway laws vary from state to state, but these are generally the laws in Oregon and Washington.