The subject line of the email was "Remote work is no longer accepted", which was posted by Sam Nissim. Musk says that if full time in-office work isn't possible, then remote work must be done outside those hours.
When Whole Mars Catalog asked Musk about the idea of a 40 hour in-office work week, Musk replied: "They should pretend to work somewhere else."
This email comes during a return to work migration for many companies in the wake of covid-19 stay-at- home orders, and some employees are not very fond of a full time return to office. If they were required to return to the office full time, a majority of workers would consider quitting. Morning Consult found that 3 out of 5 tech workers were not interested in returning to work. According to Robert Half Talent Solutions, the number of senior managers who want their employees back in the office full time has gone down.
When employees are able to work from home, productivity can be higher. When comparing a six-month stretch of covid-19 stay-at- home orders in 2020 to the same time period in 2019, Great Place to Work found that productivity improved. In March/April 2020 there was a 47% increase in productivity compared to March/April 2019.
Musk's recent business moves, most notably of which was a bid to purchase Twitter that has recently gotten him into some trouble with the SEC, are not considered to be forcing employees to return to work.