Your argument is essentially "engineers at steel plants make steel, which can be used to make guns, which can be used to kill."
At some point, the chain of causality is so remote that assigning unequivocal judgments of evil becomes logically absurd. Are port scanners evil now too?
The idea that anyone working on technology that could be used for surveillance is morally culpable is flat wrong.
People have died because of fertilizer and particle physics. It does not make chemical engineers or physicists evil.