Back in the good old days, when Google wasn't evil and Microsoft were, we'd call these practises "Embrace and Extend". The only worse thing than Microsoft not using an op[en standard was when it started to, because you knew they'd do something subtly different, or require some extension, or ...
Google have been doing this for a while with email. They started out by having IMAP support, but it wasn't quite the same IMAP as the one in the RFC. Then they required their own authentication technologies instead of the ones the IETF produced. Then they turned off IMAP by default, saying it was only for mobile anyway, and smartphones could use their gmail app.
Then DMARC came along, entirely outside of the IETF, and everyone needed to do it because otherwise Google (and a few other huge providers) wouldn't accept your mail anymore. Never mind that mailing lists broke. They had Google Groups for that kind of thing.
Now they're busy telling us how we have to authenticate mail servers; only they're driving this one through the IETF. Mid-sized providers all use DANE already, but Google would prefer not to, so everyone will have to do something different.
With XMPP, they did much the same, only it was much more violent - there were no other huge providers using XMPP, so they just stopped it working one day.
Google's mission is to organise the world's information; but their choice of how to go about it involves controlling that information.
We're a place where coders share, stay up-to-date and grow their careers.
We strive for transparency and don't collect excess data.