3D gamers can also run the display in non-Retina mode. I don't get why that's even a complaint...
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Link to such a ruling ? The people running the HDMI standard have no force of law. Adapters are not illegal. They might not be sanctionned by a standard body, but they are not illegal.
DisplayPort is a VESA standard while HDMI is managed by the HDMI Forum, an industry association.
EDIT :
http://www.vesa.org/displayport-developer/about-displayport/
VESA even markets DP as fully HDMI compatible as far as transport of Video/Audio. Devices that support DP++ are dual-mode and will sense if a display is connected through HDMI, switching the signal to straight HDMI, requiring thus only a completely passive, pin-to-pin adapter. This is all baked into the DisplayPort standard. Of course, you don't get the added features of HDMI such as CEC (a remote controlling standard so that a single device can control all its connected devices through its own interface) with this method, only Video/Audio transport.
So in essence, you're not just wrong, you're completely off base with your comments.