As someone else said, it’s “may” use full lane, not “must”. You don’t necessarily have to use the full lane all the time, but there are times that it’s definitely advisable, the times that it’s not safe to be passed. When it is safe to pass, you can ride more to the right to facilitate passing.

I find on 2-lane roads like this that motorists are entirely willing to cross the double-yellow line to give enough passing distance *if* there is no oncoming traffic. (I am in Maine, our 3-foot law says that motorists are allowed to cross the double-yellow, but OTOH, I don’t think very many of them know that; I think they just do it anyway.) The key is to be aware of the situation ahead that would prevent them from moving over, either oncoming traffic or blind spots such as curves or hill crests. When approaching these situations, it is best to move over to the center of the lane at an opportune time, giving any following traffic adequate time to react. I find it helpful to give a “stay back” signal (left hand out, pointing down, palm back) as I do this, and at frequent intervals while controlling the lane. Communicating this with the motorist behind you reinforces what you are expecting of them, and they very likely understand the reason. Once the oncoming traffic has passed, or you are past the blind spot, when the way ahead is clear for them, you can move back over slightly more to the side, like maybe 1/3 into the lane, and give them a friendly wave, communicating both that it is now safe to pass, and that you appreciate their patience. This actually works really well. Once I was even thanked by the motorist for helping him, when we happened to meet at the restaurant parking near the road where this happened. (Maybe he was a cyclist himself and understood what I was doing better than most.)

BTW, there is an updated version of that Facebook graphic:

https://www.facebook.com/photo.php?fbid=306443252797468&set=a.283448488430278.59826.281417585300035&type=1&theater

We don’t have lots of bike riders in my area, and I can really tell when I go on a road where they’re not used to seeing cyclists. People pass much less safely on those roads, and that’s when I move into the lane.

It goes without saying that I avoid roads like this as much as possible, because I hate feeling stressed over this stuff. But in some places, there just aren’t alternate routes. Having to cross an interstate highway is like having to cross a river: all the routes are busy, and there aren’t many of them.