They want Tesla to maintain that original "Elon sleeping under desks", all hands on deck, Tesla hunger of yore. To them - they probably were concerned about the design teams getting to soft from WFH and getting uppity.
A star worker for them is someone who works 16 hours a day, adds 10K lines of code and sleeps under their desk. Not someone who goes for a long walk in the park while thinking deeply about the problem, and then spends half an hour at the keyboard refactoring to remove 1000 lines of code and clear a major performance bottleneck.
Elon may be performing for his shareholders, but if he was actually smart he'd be informing them. It's notable how many of the actually-smart rockstar CEO's didn't seem to care what their shareholders thought.
"People are getting annoyed by these implicit class differences in our organisation, what do we do?"
"Let's encode them explicitly in the contracts. Then we can blame it on the contracts and pretend it's out of our control!"
The challenge for Elon (and Amazon) is that his two of his companies rely on physical labor and can't outsource the physical part but still need tech talent that could WFH.
I don't envy him...