Consolekit was iirc a xorg foundation project sponsored by xorg, and hosted by xorg.
Sources for this? As far as I know ConsoleKit has never been sponsored by anyone, even less so by the Xorg foundation.
It is hosted by freedesktop.org, which is really a different entity than the Xorg foundation, but the fd.o charter makes clear that stuff hosted there is not endorsed in any way: fd.o is just a neutral dumping ground for stuff that may be used by multiple desktop environments (eg. Mesa, harfbuzz, and ancient and deprecated stuff like hal).
vitters himself pretty much admitted he was pointlessly and groundlessly insulting the project.
Sorry, but here you're exaggerating a bit: "getting limited maintenance" may be a mischaracterization of the situation, but is definitely not insulting. That said, I'm not following ConsoleKit2's development, but the https://github.com/ConsoleKit2/ConsoleKit2 log is not exactly fast paced so I can see from where Olav's observation may come.
Well, lennart pottering failed, as he was the maintainer of consolekit who abandoned it for over a year.
Uhm, no? Lennart left the project because he saw architectural problems that where hard to fix without what would have been a ground-up rewrite of the interface. Given the generally positive comments coming from every DE and display server developer I've ever heard about the logind interface I'd say that Lennart was right.
Martin Pitt picked up maintainership for a while after him, before leaving due to other factors (Martin does a lot of great things already, but I guess he can't do everything). Given his experience on ConsoleKit iirc he already worked a bit in the past on logind and since then he's been the one putting most of the effort to move Ubuntu to systemd.
So you have people who know ConsoleKit well that decided to work on a ground-up rewrite (logind) and people who apparently seem to have started caring about ConsoleKit that didn't pay attention to it for years. As I see it, there's really no failing on the systemd side.
Consolekit2 developers ARE doing the work. While GNOME developers are saying "Any work you do is pointless. We've pulled some support for consolekit out of 3.16 and we're going to pull the rest out in the near future and GNOME is dropping all support of consolekit beyond 3.16.
That's not what Olav's post said. The emphasis was on the fact that broken code has been removed, with clear pointers on how to reintroduce it if anyone is interested in fixing it. It was announced in multiple locations: the intent was clearly to get the attention of anyone who cares and is willing to do the job. At the moment nobody is stepping up.
It seems obvious to me that if nobody cares about some piece of code, that code will bitrot and break, and it will be eventually removed.
The message here is that now is the time to act if you care about the ConsoleKit backend, as it has already shown sign of bitrot. Step up to maintain it and there will be no reason to remove it.
What would have been sane is for GNOME to have created some sort of session management abstraction that was session manager agnostic. It would have been less work for GNOME, and less work for pretty much everybody else.
That's exactly how the code is laid out now. The point is that if nobody will maintain one backend of the current abstraction, said backend will bitrot and break.
No... it doesn't need a constant effort to be kept up-to-date. GNOME publishes it's session management interface, and sticks to it.
That's not really how software works in the real world, sorry, I won't even discuss this kind of claims.