UK had a few million protest against the second Iraq war, and still didn't stop it. Do you think the percentage is higher or lower in Russia, with all its propaganda?
Worse, in the context of "picture myself working on something like this and sleeping well at night", consider sub-group modifiers: how many people in the UK resigned from defence companies due to agreement with the anti-Iraq-war protests?
Propaganda, and arresting dissenters, makes it difficult for the *average* Russian to realise anything is wrong.
But even in free nations, people like to think their soldiers are heroes rather than villains, and reports of crimes are covered up or brushed aside.