Idiotically dangerous, for two reasons. The qualities you would eliminate are the very ones that help our survival as a species. Second, and more important, wars are always about population pressure and competition for resources. Always. Your virus could poop Valium and morphine -- but it wouldn't change the root cause.
No, rarely. The Second World War was party about resources, in that Hitler wanted lebensraum, and the proximal cause for the USA getting into the war was Imperial Japan's desire for the oil and territory of the Dutch East Indies. But Japan only wanted to take that because its wars of conquest got it embargoed. Had it stayed peaceful it could have just bought the oil, a much cheaper prospect. So, it's more like the oil was an issue because of the war, not the need for oil causing the war. However, Vietnam, Korea, WWI, the American civil war, and the war for independence... what resouces are you talking about?
...wars are always about population pressure and competition for resources. Always. Your virus could poop Valium and morphine -- but it wouldn't change the root cause.
You're begging the question. There is no 'be violent' chemical in our brains. It's a complex emergent behavior. So your hypothetical virus would either be ineffective, or so effective it make the organism (that's YOU) unable to feed itself.
Decreasing our testosterone would reduce violent tendancies, but it would also mess with our ability to reproduce. And besides, war isn't usually about irrational aggression, it's often more about fear, which afaik is mitigated by testosterone
