Why would General Anemone do that? Because he sees Salmon Run as more than just an extra thing that Inklings and Octolings can do, he sees it as not having to send tentacle Octarians to fight the Salmonids. So if Grizzco workers don't want to do things for Grizzco, then the Salmonids, which are the enemies of the Octarians who live in Inkopolis, will attack the Octarian neighborhood.