Everybody. Getting the general populace that has no interest/stake in the matter involved is literally the point of protesting. The oppressor doesn’t care if you make a racket about the boot on your neck, they’re not going to lift their foot because you asked nicely.

But if you make enough noise that everybody has an opinion on it/gets involved, now they can’t just sweep it under the rug and wait until the oppressed run out of resources to keep up the protests.

Civil Rights didn’t get passed because a bunch of people handed out pamphlets or something, they got passed because a million people ground the entire city of Washington D.C. to a halt. They got passed because a black WW2 vet trained a militia in the Bible Belt to protect black kids and their families using sandbag emplacements and machine guns to keep them from getting killed by the KKK for daring to go to white kids’ schools. They got passed because several billions worth of property was burnt to the ground across the entire nation after MLK was assassinated. Years of protests got politicians to wring their hands. A week of burning cop cars and city districts had the bills drafted, voted on, and passed.

If you can’t get the attention of the people who don’t have an interest and at least attempt to change their minds, then you’ve failed. You may end up turning people against you, but I guess that’s a risk you need to take. Part of the point of protest is to bring injustice into light so people who haven’t been paying attention may finally do so.

Other citizens that don’t have an interest/stake in the matter?

You mean the people who don’t mind fascism?