As in, we have no other choice. They could write a clause that said your third child must be named Macintosh and everyone would "agree" to it because there is no other option.
That does not mean it's right.
Consider this: It's the late 1990's and the Terms of Service for Microsoft Windows contains "10.4 Apps that create alternate web browser environments are not allowed".
Microsoft has its pants sued off in court and is almost forced to break up as a company.
I'd argue that Apple has far, far more control that Microsoft ever did, but face no similar consequences for any of their anticompetitive behavior.
That's what upsets me about this.