Im always confused by the use of "quietly" in headlines like this. They publicly stated they where going to stop posting on X and then multiple stories come out about it. That's the opposite of "quietly".
In my unpopular opinion I believe a better approach would be to stay on the platform and only use it to let people know when there are updates on their own platform, website, forum, etc... Let citizens know up front that interactions will only take place on their own platforms and that comments on X will not be replied to and then set up automation to delete any comment that is not theirs or block external comments. There's always a few cops that get assigned a desk job that could find themselves useful maintaining such things.