Ackshually, bloodbaths were rare in ancient warfare. The losing side will often break and flee before being slaughtered. The winners usually let the enemy flee because the risk of getting injured (pre-antibiotics) AND the LOOT. Soldiers join up for the loot (and pillage, and rape). It is one of the few ways a commoner can get rich quickly. Fleeing armies often throw away their weapons, armor and baggage trains. Everyone will then return to their villages and go back to being farmers until the next warring season, maybe under a new flag.
Breaking and fleeing is usually why one side gets slaughtered in Classical-era warfare, and taking war trophies from the bodies was an important incentive if you weren't on the cusp of breaching their even more loot-filled camp.
Media's a relatively recent tool. If you mean proper, national-scale wars, very few were set in motion by regular people. Before the era of the nation-state, most wars were over dynastic or feudal disputes, or else naked imperialism. Wars set in motion by regular people would've been more like clan feuds and the like, which, while often vicious, are generally not large enough to be historically noteworthy. Some religious rebellions and the like would've been started primarily by ordinary people, like the Hussite Wars. Mass migrations and border feuds that steadily become larger in scale would count too, probably.
It started over a dispute about a poor American farmer shooting a rich British farmers pig who escaped its pen and was eating all the poor farmers crops. Also despite being a war it was mainly posturing by both sides, I don’t think either side actually ended up shooting at each other. Instead they just kept making ramparts and barricades all over the place and then stared at each other across from them.
Not made by me - I'd never compare the NOBLE VOLUNTEERS OF THE ROMAN EMPIRE with a bunch of Vatniks, and if I did, I'd note that Roman soldiers were protected against rape by their superiors - and Russian soldiers are not.