1: then they would go after literally anybody running a node
2: their client will not see peers on another IP. It will just see their own I2P node. Any I2P aware software will also not have any IP addresses as peers, only I2P specific internal addresses. They will not even be able to associate an incoming connection to any one node without understanding the I2P network statistics console.
3: by this argument all anonymization tools should be illegal, Signal too, etc, and nobody should help anybody maintain privacy. In the real world there’s plenty of reasons why anonymization tools are necessary. And there will be literally zero evidence tying you to a crime. Preexisting legal precedence says an IP address alone is not enough.