Was GM CEO fired because he donated to Republicans & Blue Dogs?

A presumably lefty/socialist blog thinks that the former GM CEO was fired because he donated to conservative candidates, both Republican & Democratic:

In 2008, with Democrats firmly in control of Washington, despite GM's efforts, the PAC started donating about equally to the two parties. Last year the top non-Michigan recipients were John Boehner (R-OH), John Cornyn (R-TX) and Mary Landrieu (semi-D- LA). And although they were about even on Democrats and Republicans, many of the Democrats they contributed to are Blue Dogs and other corrupt corporate-oriented Democrats

I suspect that DownWithTyranny equates "corrupt" and "[free market] corporate-oriented" as synonymous.