[tosser0001]

That doesn’t seem particularly fast of a spin and I’m surprised it’s the fastest one observed.

There is a moment in 2001: A Space Odyssey that I’ve always liked. It’s at about 1:13:15 or so, and is just a distant shot of the Discovery One. Suddenly two space rocks silently tumble past. I like the scene because it gives a sense of the scope and silence of outer space, but I suppose it would be incredibly rare to be so close to even one rock, let alone a pair. And they are tumbling at about the pace measured by the one in that article, so perhaps even rarer still.

[WJW]

Well as the article states the bigger ones would tear themselves apart if they spun too fast so that is one reason. In the end they are just big rocks and thus not very good at tensile loads...

[fsmv]

They're often more like gravel piles than a single rock. We learned from the DART and OSIRIS-REx missions.