Most people will become sufficiently violent if unhappy enough. The world's always three meals from anarchy.

Sometimes. On the other hand a surprisingly large number of women are raped and dont fight back because they are overwhelmed with various forceful factors. I imagine being raped feels quite unhappy, possibly even more so than missing 3 meals.

I'll have to look more into the 'seasoning' islands full of slaves in the Caribbean during the slave trade years. IIRC they were treated as bad as you can get, were the majority, and didn't consent yet practically didn't overthrow their dictator in most circumstances (Haiti might count as an exception).