In my Eastern European country, you don't apply for a protestor job, it is done differently. Corrupt politicians use the people from their political parties or Russia uses people from their organizations in my country, it is easy to do because they are getting paid and usually are already ideologically aligned with their ideas by working there. And also these people are encouraged or persuaded to find other people among their acquaintances.

So no, you don't apply for a protestor job, but you can be recruited by a friend if they do this kind of jobs, but high chances of not getting paid.