I've ridden on these both in the Netherlands and, of all places, Cambridge (our fair city) MA.
First, they don't belong everywhere - and that's OK. It's absolutely not a bug that these shouldn't be on rural twisty hilly woody roads.
Second, think of it as VERY similar to how we all drive (AND RIDE) on very low traffic narrow neighborhood roads. Really, with no centerline, do we all REALLY drive on "our half" of the road 24/7/365? Are you all *REALLY* saying that you don't drive a bit far from the curb (if there is a curb). Are you all saying you REALLY don't partially cross the missing "center line" on such roads when there isn't any traffic? Are you all REALLY saying it isn't NATURAL to move right when there is oncoming traffic? Finally, how do you get home when there's a parked car in the way on a narrow road? Let alone, a parked car on BOTH sides on a narrow road?
This is how it often works, as shown the video. People drive in the middle-ish of the the road, move over to pass each other, and then move back to the middle. EVEN when folks "cheat" toward the curb (when there aren't many bicycles) the move into the "passing lane" and move back when safe just plain old works.
All this said, the people who lived on one of the streets in Cambridge where it was tried HATED IT. LOATHED IT. They rebelled, and got it reverted to be sort of conventional. Except, and this is the ironic part really, there are now big GREEN SHARROWS in the middle of each lane showing that bikes belong here too. And the people who live on the street LOVE this new layout, and now just wait behind those of us on bicycles, because, it's only a short road (goes past where e.e. cummings was born), and there's no use in rushing up to the stop signs at one end or the stop lights at the other end anyway.
Finally, for those who are freaking out that in some places in the Netherlands people WALK in the road, well, yeah, almost as many people walk on those rural roads as ride bikes or drive. (And I don't even want to think of what you'd all think about the "just paint" sidewalks in Taipei, where MORE people walk than drive or ride bikes, but honestly scooters rule those roads.)
(Oh, one last finally. Those who worry that one way roads will become two way roads. Most of Ireland. Some of the "two way" roads are so narrow you have to back up to find a place to pull over.)
-mr. bill