The ad was posted by a company called "Crowds on Demand" and offered $25 per hour to "actors and photographers" to participate in events in the "Charlotte, NC area."  While the ad didn't explicitly define a role to be filled by its crowd of "actors and photographers" it did ask applicants to comment on whether they were "ok with participating in peaceful protests." 

Here is the text from the ad:

Actors and Photographers Wanted in Charlotte

Crowds on Demand, a Los Angeles-based Public Relations firm specializing in innovative events, is looking for enthusiastic actors and photographers in the Charlotte, NC area to participate in our events. Our events include everything from rallies to protests to corporate PR stunts to celebrity scenes. The biggest qualification is enthusiasm, a "can-do" spirit. Pay will vary by event but typically is $25+ per hour plus reimbursements for gas/parking/Uber/public transit. For more information about us, please visit www.crowdsondemand.com

So what is "Crowds on Demand?"  According to their own website, they're in the business of sourcing large crowds of people to "provide clients with protests, rallies, [and] flash-mobs" all over the country.  They even have an entire page on their website dedicated to "Protests and Rallies." Silly question, but if your cause is worthy of protest then why would you need to pay $25 per hour to get people to show up?