Why did people protest against segregation and discrimination?

1) The people who were discriminated against felt they were treated unfairly and wanted to be included in the society - this was their reason

2) The people who were not discriminated might have protested for a variety of reason: they sympathized with the other group, they felt that a society where some people are discriminated is not a society where they want to live, or simply they held the values that all humans are equal.