I feel like everyone's totally missing the point of that Destructoid thing. His firing isn't what's unethical, they were well within their rights to do so. Blacklisting him is illegal though. Telling other media outlets not to talk to him is unethical.
I don't give a shit about the goals of Gamer Gate or ethics in the gaming press, but regardless of what anybody says I think that's a pretty damn good example of corruption.