If 9/10 were already voluntarily coming into the office every day, I could see it. Of course it would only be 9/10 of the people he bothered to speak to it about, and maybe he only spoke to people that were already there.

As to why they would care if they were already there, well one guy in my team goes in every day of his own accord. He applies pressure to everyone on my team to be there with him every day, in spite of the stated WFH policy. So everyone but me goes in every day because I’m the only one that is willing to disappoint him. I’m reasonably certain that guy would love a forced into the office every day mandate, to force me to be there too. Then he could stop making passive aggressive comments about how people who didn’t come in must not care about the work as much as they should at every opportunity.