[smashingfiasco]

Implementing CSRF doesn’t stop an outside party from finding out that you have (for example) an AppleTV inside your network. The device will still return a HTTP status code. You could legit spy on end users this way. A real boon for ad tech, too.

[Avamander]

Such specific detections could be countered by Apple, it serves no good adtech purpose if they can determine some small amount of devices existing on a LAN.

In general though, this isn't be a problem on proper IPv6 LANs and instead of buggy and cumbersome workarounds being built into browsers we should just switch.