Can you import some of those polite riders to CO? Not only do they not line up single file and maintain their space when there is oncoming traffic and someone coming from behind, they will go 3 abreast. And inevitably they’ve brought a female or a beginner rider along with them who can’t keep up, so they all have to slow down for her.
This is not to say we don't have some share of a**hole riders but it sounds like that species is much more common out in your neck of the woods. Unfortunately, a Darwinian cull may be the only way for your bicycle herd to learn its manners.