Which is not unique to AirPlay2. The problem is, everyone has their own technology: Spotify Connect, Chromecast, AirPlay, there are others. In a consumer-centric world, there would be one all-encompassing standard. But there isn't. And let's be honest, any audio equipment worth its salt supports a bunch of them. Hell, my 10 year old budget Denon receiver does.
If you use Spotify, you already have choices within the App for casting, including multicasting. Hence my previous message: This is manufactured rage over a margin feature.