It is a coincidence. The issue is commands in the game clashing with the browser, an environment it was never meant to run in. Whatever command-key you want to use for shortcuts, both applications have equal claim to wanting to use them - is is about application shortcust vs. application shortcust not OS shortcuts vs. application shortcuts. It only works out because the game was developed for a different platform than the browser, which by coincidence uses a different key for commands.
It is a sort of coincidence that Apple decided the pinky finger button should be control rather than command. The other way around and crouch-jumping would be more difficult and you'd want to rebind it... but you would then run into the same keybind overlap issue as experienced on Windows/Linux.
Not really a coincidence and that's not the only scenario where it's preferable to have a dedicated command key