> This isn't law so aren't we a few hours from this being put on injunction?

That’s possible; it is also possible that it isn’t. And it is possible that even if it is, we are a few days or weeks away from an appeals court retroactively invalidating the injunction and allowing cancellations of visas based on failure to return when the injunction was in effect, or else “only” with immediate effect when the injunction is lifted.

If you are an employer who wants to keep your H-1B employees, you probably don’t want to gamble unnecessarily with this, you want the employees to act in a way which minimizes your risk.