So the fact that the Vajra are VERY GOOD at blowing sh!t up (or should I say were very good at it...?) makes them unsympathetic? They're being played, most likely. Our heroes are also (again, most likely) being played, and are doing the bad guys' dirty work for them.
Perhaps my earlier words were ill-chosen...SMS are not bad guys, but they are doing what the bad guys want. So yes, they're still heroes, but their current job is...less than heroic, let's say.
And if the thoery that the Vajra are either being provoked or were somehow altered to become aggresssive doesn't lessen the enormity of their actions, but it does absolve them of some of the responsibility. The way it looks (to me) now, the Vajra are a weapon, and Galaxy is the person holding the weapon. If that weapon kills someone, who's at fault?