The following video from Google’s head of search spam, Matt Cutts, states that the Big "G" will not penalize your website just because you bad mouth them. Cutts also gets into the standards that Google uses for manually removing spam from their search index.

From the video: “One thing that we don’t do it is just say " someone has been critical of Google, therefore take action… So just because you’re critical of Google that’s not the sort of thing where we’re gonna mark you as spam.”

The rest of the video goes on to explain some of their webmaster guidelines.

Click here for the video.