Some people have a desire to be segregated from those they feel superiority over. It's tribal, they want their own tribe to prosper, and political affiliation is the only acceptable way to fulfill the primitive need to be in a tribe and see that tribe thrive.

Putting a sign in the window of your business with your tribe's affiliation on it is akin to a "no coloreds or Italians need apply" sign back in the early 1900s. Keeps the riffraff out and encourages business with those you feel kinship with.

It's too narrow, the hillside is cut too steep, and traffic tends to be erratic. It's not safe in any way to put a bike lane on 28.

My geology professor in college remarked on the insane steepness of the hillside along 28 and how some of his colleagues refuse to drive on it due to this. That hillside is not naturally formed, it was cut with machinery in the 1920s, highway construction inspection on federal aid projects wasn't a thing til 1979. I wouldn't want a bike lane installed near it.