Those campaigns were surrounded with violence. That is why they worked. Riots, killings, people getting beat up, people fighting police. the police committing acts of violence, etc. Just because they aren’t an armed concerted effort, not having concerted, armed, resistance, does not mean non-violent. Like you say the threat of the violence they could see, getting bigger, is the reason to reach out to the non-violent party for diplomacy. But the threat has to be real.