Well, for one thing, Prenda Law controlled the entities (or they were completely fictional) that were the plaintiffs in its cases, whereas the "reputation management firms" here are apparently filing cases with their reputation management clients as named plaintiffs which the clients apparently don't know about and don't approve, and object to once they are actually made aware of them. And they use the results to influence third parties besides the defendants, and the defendants aren't generally doing something that they want to hide from attention.

From the appearance of what is going on here, there are lots of reasons to think that this scam could blow up much faster on its perpetrators than Prenda Law measured from the first time someone noticed something funny going on.