They don't demolish anything. Obviously we all know about examples - Gintis even mentions the hoary example of Mondragon  and clearly, you didn't bother to read before lecturing. And nobody said "all co-ops become managementized" - that's something you made up - or "pulled out of your ass" to use your own phrasing.

I'm sure capitalism is shaking in fear at the continued existence of an upmarket grocery store co-op, though, so I await the revolution ASAP.