To be clear, you can use AirPods with an Android device for audio.
It’s the extra convenience features integrated into iOS and macOS to change certain settings that have been reverse engineered here. And you can’t actually even use them without rooting your phone and applying a patch to Android’s Bluetooth stack.
A device sold not in small part due to its noise cancelling ability, yet having no way to turn it on/off when connected to Android is not an extra convenience feature.
It’s the extra convenience features integrated into iOS and macOS to change certain settings that have been reverse engineered here. And you can’t actually even use them without rooting your phone and applying a patch to Android’s Bluetooth stack.