Pretty much every news publication / organization has some internal bias / lean (some more than others). That does not mean their reporting is inaccurate.
Some internal bias is one thing, if it is disclosed. Mother Jones, however, is a bastion of extreme leftist rhetoric that tries to pass itself off as a legitimate source of news. That is the part that is disturbing and very misleading to those that haven't been warned about or don't already know about the site. Maybe some sort of logo, even an arrow pointing to the left or right, or a Chrome plugin that turns the site blue or red for a few seconds when you first go to a page on it, would be good for these kinds of sites.