You know what, good for Google. I hate to sound like a child, but Amazon fired the first salvo by dropping the Chromecast a few years back. This move only seems fair.
Didn't Google block the ability to stream to Chromecasts? I'm not justifying anyone's behavior here but this is why the "they started it" argument is considered childish. These are all anti-customer moves which will hurt both companies in the long term.
IIRC, they made backward incompatible changes to the protocol (which I don't think was ever public, but had been discovered and independently implemented) which effectively broke apps not using the official API implementations (which are limited to Android [Play Services, not AOSP], iOS, and Chrome [not Chromium, AFAIK].)