In fact, those social media sites have been used to manipulate foreign militant uprisings and sway political discourses (whether in the U.S. or in other countries).
Also, people who worked on GPS technology are directly responsible for the GPS-guided missiles that have been fired into Syria and other parts of Middle East. Should those people be ashamed as well?
Facebook, Twitter, et. al. are first and foremost data-mining ad agencies that also provide social networking services. The fact that you can also use them to target terrorist is not really a by design item, much like even though you can beat someone to death with a wrench, it's primary function and the design goal behind it is to secure nuts to bolts and screws.
So yes, there is a bit of a difference when Google's tech happens to also be used by the military for image analysis from drones and when Google willingly assists and participates in such projects.
The major concern a lot of people have is that it's a very big switch in market from what they were doing to Project Maven. People who otherwise were maybe concerned, or heck, even satisfied with Google's influence on their lives and happy to participate in reCAPTCHA and pay for Google services now find their work and money being used to pay for something they disagree with.
I do not appreciate the simplification of the outcomes, as no civilized society judges in that way - we consider the motive as well as the outcome, as well as the state of mind of the person who committed the act. Likewise, there's quite a bit of a difference in US Army RnD grabbing an open source project and embedding it into drone guidance systems and Google taking a Government Contract; aside from the willingness of Google in this state, they demonstrate their complicit nature as a company via the contract and the payments; the open source project likely wasn't even aware of it until they read about it in some news article or saw snippets of their code in a Press Release/Demo.
* I realize that this is meant as a method of judging guilt (hence Guilty Mind), but the concept is the same here. The state of one's mind in making an action should be relevant.
yes, and not only for the reason you listed (although that certainly is one)