Android sort of gets a pass in that it's something that's constantly used by the user, so there's some ability to train people into arbitrary and unclear UXes,

Android sort of gets a pass in that it's something that's constantly used by the user, so there's some ability to train people into arbitrary and unclear UXes, especially if they're only a few buttons (a good example is game controllers where what buttons do is completely disconnected from the letter or symbol they're assigned). iOS is pretty similar in that a good number of the navigation gestures aren't super intuitive and not really discoverable until you build some muscle memory.