Because the apple argument was different and that’s what matters.
Apple designs, builds, and sells iPhones/iPads
Apple wrote the ios which only runs on iPhones/iPads (within technical reasons) and are the owners of the code.
Google however, does not build phones. Apart from the Pixel phones. Samsung designs and builds phones, LG use to design and build phones, but would install Android.
Android while mostly maintained by Google, is not owned by Google also was not originally created by Google and can be run on just about any arm64 device not just things created by Google.
In the lay terms of you purchased a PC from Dell running Ubuntu and could only install applications via the Microsoft Store you would be pretty unhappy.