alt Hacker NewsApps requesting an age is not extraneous and there are many legal and safety reasons why an app may collect this information. If the operating system doesn't do it you run into the cookie banner situation where every individual site has to implement a dialog box asking the user instead of there being a standardized way to do it.
Except the cookie banners are also optional, unless you're using third-party services to collect that data. Don't blame the cookie banner, blame the dozens or hundreds of "partners" that site is using to "process" your data, blame the site owner for building such a travesty of a page that they have so many "partners" in the mix harvesting extraneous info unnecessary for basic functionality instead of building a better, cleaner, leaner, targeted service.