Read Google's post again. That's where it's explained. Note that the following is not necessarily my opinion, but my interpretation of Google's post.
Google believes that a cartel of competitors formed to combine resources with the main purpose of using those resources to bid on IP to use against Android. The winning bid didn't reflect any individual competitor's valuation of the asset, but rather the aggregate of their valuations given that they all plan to use the asset as leverage against Android. Google thinks this is anticompetitive.
I read Google's post and Microsoft's response and Google's update to the post and Microsoft's response to the update as well: http://techcrunch.com/2011/08/04/gentlemen-take-this-outside...
Considering all arguments, I think there is more to this story than what Google told in the blog post.
The fact that they did not even mention that they were offered to be part of the joint bid in the initial post raises a lot of questions.
Its fine for you to think that. I'm just discussing the merits of Gruber's post. I think he is trying to spin as whining what Google believes to be a legitimate claim of anticompetitive behavior.
Google believes that a cartel of competitors formed to combine resources with the main purpose of using those resources to bid on IP to use against Android. The winning bid didn't reflect any individual competitor's valuation of the asset, but rather the aggregate of their valuations given that they all plan to use the asset as leverage against Android. Google thinks this is anticompetitive.