I think it's employers playing the game and optimizing. Full-time employees are salaried. They cost the same no matter how much work they do. So full-time empl

I think it's employers playing the game and optimizing. Full-time employees are salaried. They cost the same no matter how much work they do. So full-time employers want them to do as much work as possible. They view time as zero-sum, so any hours you spend on another job are hours you could have spent on them. Even if - as we all know - there are diminishing returns on hours and those hours at job 2 would not produce the same output if pumped into job 1. So, as always, full-time employers resort to soft power and psychological tricks to exert control over salaried employees. And I'd say it's increasing lately because remote work as shifted the power imbalance and employers are realizing the other side of at-will, salaried employment is that employees can work as little for them as they can get away with so long as they are good enough to remain willfully employed.