Yeah, I think everyone is assuming that the email and layoffs are causally related. That doesn't seem plausible. If he really wanted to use the work-from-the-office mandate to raise attrition, he would do that months PRIOR to announcing layoffs - not at the same time.

I wouldn't be surprised if people who said they prefer not to come back to the office, will just be given the same severance package. OP should ask HR about it.