PCM passthrough on ATV

Does anyone have an explanation as to why Apple does not allow PCM passthrough on the Apple TV? My Yamaha AVR detects and displays the digital format it is receiving from the source. In the case of my cable box as the source Dolby Digital displays on my AVR when it is receiving that format. Same goes for my Amazon Fire Stick which usually displays Dolby Digital + when using the Netflix app on that device. When my Blu-ray player is the source it usually displays DTS. And so it goes. But when my Apple TV 4th generation is the source all it ever displays is multi-channel PCM even though I know full well what format I am receiving no matter what app is running. This means my ATV is not passing through the format to my AVR but is instead outputting its own format, one not recognized by my AVR. So why is Apple doing this? Is it licensing issues? Is it about proprietary output? Sure, you can set the ATV to always output Dolby Digital but that’s not exactly honest is it.

So can anyone offer an explanation as to why Apple does this? Why do they not allow the digital audio format to pass through the ATV to the AVR?