In the United States, the success in establishing rights for black people (and people of all races, really) is arguably due to negotiation and peaceful protest. The violent protests (arguably) created backlash and were counterproductive for everything save raising the issue as important.

More recently, rights and social acceptance and/or support for disabled people and for homosexuals, among others, have advanced immensely on the basis of peaceful "negotiations".

One can come up with numerous other examples around the world, but basically, economically advanced Westernized democracies became good places for advancing rights through understanding and negotiation and peaceful protest by about 50 years ago.

This doesn't mean that everything has been solved! It only shows that the method is viable and has been for a long time.