...they could probably rove around finding people with these stations.
True, though the benefit of these and other kinds of community-run decentralized networks is that it becomes harder to disrupt those networks. It's not impossible, but they're often built around an idea of, "But what if this node goes down?" so they have ways to address those issues or make it so that it's easy to deploy new nodes.
Still, if things are to the point that the government is cracking down on hobbyist radios, you've probably got lots to consider regarding the best ways to communicate with other dissidents and activists.