I would look at the final price of the McLaren. Accessories and all.OK...
Lets say that you were to buy a McLaren F1 for $X.
Would you consider the $12,000 USD wiper blade to be fairly priced? Or would you agree that for a sliver of rubber (essentially just a longer version of what is on your own car), it is a rip off?
It's not out of line with Apple's line of accessories. You can argue that Apple's official cases and dongles are more expensive than third-party alternatives, and that's the whole point - they are optional accessories.
Same thing with the stand, which is meant to be optional for its target market, because the people buying one are likely working in studios with similar monitors already mounted on VESA mounts, and so they don't necessarily need the stand, or even the VESA mount that Apple is offering, and that's perfectly okay.