That's the cost of doing business, you keep the profits and in exchange you don't treat your employees like fucking garbage.

He didn't even need to lay them off, according to the article. He just wanted "a fortress balance sheet going into the holidays"

This reads like a solution to a twisted elementary school math problem, but:

Assuming 1 manager for 10 employees, that's 90 managers each doing a 3h20 minute block of 20 minute meetings, allowing all to be fired in one morning.

Your unspoken assumption: A company of 6000 employees only has 1 manager/HR rep capable of talking to pink slip recipients.

Just over 233 person-hours of work isn't 233 hours of work. Assuming team sizes average 20, that work can be spread across 35 managers, requiring less than a business day to complete. Even assuming 900 people as mentioned in the headline, that's still less than a day's work. Larger-than-average teams may require more time, but this could still be easily accomplished over two business days.

Now do the math on all the less important meetings that you have every day.

he would have to fire 1000 people to cover the cost