This doesn't make sense, HDMI is an universal protocol that connect two devices. There is no Apple ATV HDI protocol and neither is there a Samsung HDMI as well. Do you have your facts straight?
HDMI may be a standard protocol however HDCP (high def content protection) is not.
Well, it is, but not everything supports it, and it relies on keys.
And even if it was, there's nothing to say that either apple or samsung aren't playing non-standard games. Given that the ATV works with other brand TVs, if i was a betting man I'd put my money on Samsung. It certainly isn't in Apple's interests to pull this stunt, as they don't actually make TVs at the moment and samsung have a large share of the TV market. It would hurt the appleTV more than it would hurt samsung.
I'm not sure of the exact technical definition for how HDCP works, but the general overview is that all of the devices in the chain need to be authenticated or HDCP content will not play.
If the ATV doesn't trust (or otherwise can't authenticate) the Samsung TV, or perhaps vice versa (unsure on that one) then HDCP content may not work.
In the age of digital transmission and content protection - there is a lot more involve than just the physical/electrical cable connection - there are chips in both devices that need to authenticate each other.
This means that it may be TV model specific, and may even be firmware version specific. IF an ATV or Samsung firmware version invalidates the HDCP key(s) involved (as would be demanded by hollywood if one of the keys were to leak, enabling easy piracy of HDCP protected content), it will break.
As in my last post, I say again it is your AppleTV, if all or at least many of them had problems we would have heard a LOT of noise here on MR and the internets.
IT is your AppleTV or a faulty Samsung TV or whatever cable you have.
Many posters already said to have no problems at all yet you go on with your 'rant".
Get a new AppleTV after you brought yours back, if it still gives problems let Samsung check your TV.
Did you read the diagnostic process? Multiple TVs tested, Multiple AppleTVs tested. Same problem.
Besides, evidence that a bunch of older previously purchased TVs do not exhibit this problem does NOT mean that some new TVs on the shelf today do not.
The "it works for me lalalala must be user error, noob" belongs on the Linux forums.
All of those who posted "works for me" - did you buy your TV in 2012?