There's all kinds of ways to protest: Speeches, letters, open letters, petitions, peaceful gatherings that don't block traffic or marches where the public is notified well in advance, lobbying, posting on public boards, vigils, walkouts, boycotts, strikes, lots of online shitposting, selling banned goods and services or even just doing things that hurt nobody while knowing you could be arrested for it.

There's also the Scientology model: First accrue a giant war chest and devout followers. Then when any entity crosses you, you wage a total but legal scorched earth theater of battle on the perps. Target one or more high value individuals, have them watched 24/7 with PI's and make sure they know you're watching, send followers to knock on their doors to ask questions and interview and harass them, dig through their garbage, harass their family and friends via phone, e-mail, and even open letters in publications, float rumors that make their employers want to fire them, provoke them and sue them. Eventually the individuals will crack; even if they work for the FBI (which actually happened before) and let you have your way again.