I agree with this. We have both here in NYC. First of all, cyclists need a way to get to their destination. Nobody is going to ride on the greenway and then walk a few blocks to their destination. Second of all, motorist behavior has really changed since the lanes were installed. The protected lanes are mostly like a separate route, but they still intersect the same road, and force drivers to mix in with cyclists on some turns. It can be hairy, but it's helped define space for everyone and increase safety for pedestrians, cyclists, and drivers alike by reducing turn speeds.

The article makes out that adding lanes to back roads without changing anything else is bad.

Unravelling implies that if you were to use roads like that as part of your cycle network, you stop them from being a useful through route to motorized traffic ("Filtered permeability"). When you do that you don't need the bike lanes.

As the article is implicitly about adapting existing motor-centric infrastructure I would have made a better point posting this brief video instead: https://www.youtube.com/watch?v=gdWllXfGGrg

I think it says that about separated bike lanes themselves. I can't see any reference to separate bike routes that aren't immediately alongside roads.