Well your point rises couple of questions:
1. Does Aquaman need some secret organization as adversary? It seams that every character these days has something like that and it has become just another check-list item to clear. It doesn't inspire confidence and doesn't feel very creative.
2. Now, I don't mind Abnett introducing new groups, but I think it could be done in a better way. Here they basically poped out of nowhere and supposedly had been operating for some time already without anyone in-universe being aware of them. Now, maybe Abnett will flesh them out and make them interesting in next few issues, but their introduction to me feels very generic and I think its natural to be sceptical about second act if first one is underwhelming.
Problem is simplicity, for example its easy to infer from previous issues that Aquaman had set up diplomatic relationship between USA and worked out all details required to set up an embassy on USA soil. It had public opening with representatives from various places so obviously it was officially recognized.Groups claim credit all of the time w/o the leader of the group having to pop his head up. Pretty obvious the people were from Atlantis, which points directly back to the King
Now, what happens in this issue? Embassy seams to be on lock-down and nobody knows why, what would realistically happen here? USA would make some statement on why that is happening or at least inform Atlantis that deal is off and you should all go home. None of that happens, how Aquaman decides to respond? Goes to see Mera and they decide to walk to the White House. He doesn't bother to contact government of Atlantis to find out if they know something about it, he also doesn't bother to make an appointment with the president, assumption here probably is that president just sits all day in White House waiting for someone to see him. Then he gets arrested for dubious reasons, its stupid not because groups claim credits without their leader showing his face all the time, but because Atlantis is not a terrorist group, but a sovereign nation and here you got head of the state saying that he doesn't know anything about it, natural outcome would be to get things cleared up and Aquaman making some kinda counter-statement, not him getting arrested.
Now, I understand that such details might not be interesting to other people, but they are interesting to me and thats why I'm finding whole political angle of Aquaman lacking.