When you buy a lot of computing equipment, there's a clause in the contract saying that you can't use it to control a nuclear power plant. Do you own the computer?
That doesn't mean people can't be upset that there are limitations placed on how you can use the software. Imagine if you were told you couldn't use Microsoft Word to write about certain topics, for example.
This clause is more like Microsoft saying you can't use Windows to write software for Apple computers.