Should he have been fired?

I was all in favor of firing him on the grounds while his statements are (presumably) true, they do nothing which generate money for the site and given the apparent backlash do the opposite.

Then I saw the rest of the articles. No way should he be fired. If the site chooses to cater to a particular demographic and actively seeks/encourages authors that meet this target audience, the author cannot be faulted for doing his job. The article did not appear to be any more provocative than usual for the site so I must conclude the site's chosen political/social orientation caused this backlash, not the author himself.

Summary: You should not be able to fire people for doing their job.