Double standards redivivo. Dominguez was apparently thrown out to make room for Carlsen after Bazna was suddenly canceled. Again quite a non-ethical stand by Carlsen profiting at someone else's expense. But somehow you prefer to make a big deal about this little mistake of FIDE.
Better focus on the good news here.

Btw, obviously all players have been contacted by FIDE before the list was published as can be derived from both regulations tournament choice of the players.

There was at least one occasion when a player was forcibly removed against his own wishes: Gashimov (another participant in the GP story) at Reggio Emilia last year - he heard from colleagues that he's no longer part of the field. The fact that Dominguez doesn't talk about no longer playing Biel doesn't necessarily mean that he is happy with the turn of events, and even less that it was his own idea. I mentioned this case on a German blog, Stefan Löffler mentioned earlier today that dominguez gets a Biel 2013 invitation as consolation prize from the organizers, is this it??

It's another story that (other) players asked to be released from their contracts for whichever reason, and organizers complied explicitly stating that a player dropped out at his own request.

I would find it hard to believe that Dominguez cancelled Biel (21 July - 3 August) to prepare for London starting six weeks later. There is the Olympiad in between ending ten days before London - where all London participants will probably play but Svidler who didn't make it on the Russian team. Dominguez is or was used to busy/busier schedules - during the brief period when he and Wang Yue were the best players from North America and China and got invitations to almost all supertournaments.

At least the alternative interpretation seems equally likely: Carlsen invited himself to Biel, more or less "claiming" a spot, and someone else had to step aside.

Regulations are pretty clear about this: Players indicate their prefered GP tournaments in advance, so it's far more likely that Dominguez already knew his schedule.
And besides, the Biel tournament isn't at the same time as any of the GP tournaments anyway!

It is far more likely that Dominguez "withdrawal" from Biel has nothing to do with the GP. The fact that the news of Carlsen participating and Dominguez "retreating" at Biel was announced at the same time points in the direction of a simple trade by the organizers. That would also explain why there is no reason given for Dominguez his leave on the official site.
It would be quite unethical but it's the most logical explanation and it would be nice if some reporters could get more info on both incidents to be sure.