Well it's tricky. I don't really have a problem with google owning the .google TLD, because that is a pretty unique name, and is unlikely to be useful for anything besides unrelated to Google. Similarly for .walmart or .microsoft. But .apple is a problem, because it is a common English word, and it isn't unreasonable for say an apple orchard, or an apple cider company to want a .apple domain. Similarly for other brand names like target, zoom, uber, plaid, etc. Even .amazon fits here since it is also the name of a river, a rain forest, and mythological group of women.
But where do you draw the line? How do you decide if a company should be allowed to get a gTLD for their brand? Clearly, having a trademark is not sufficient, as it is possible to get a trademark on a common word, and it is possible for multiple companies to trademark the same word as long as there isn't a risk of confusing them. Is it fair to let google and microsoft get such TLDs for their brands, but not apple and amazon?
