keyboard slacktivist
An activist interested in any social issue who fails to actively participate in person as a change agent. Instead, this kind of activist sits behind a computer keyboard trying to effect change using social media as their sole forum for activism. These activists are not actively engaged in the cause in person or in a physical sense.
Some protesters picketed the company to try to get the company to change their ways, while the keyboard slacktivists took up the cause by posting only on Twitter and Facebook.