> I guess the part I don't get is how having a message in the email signature of your work email can be construed as expressing a personal opinion.

If that were the entirety of your argument, I'd actually be in agreement with you. It wouldn't surprise me if this decision got overturned on those grounds.

But on your second point, the current Court expressed its views on compelled speech and the First Amendment as applied to government workers in the Janus decision and this judge is merely following that precedent. It is stated very clearly in the decision.