Depends.That's not really what the point was about.
This is not about how you treat people in social situations.
This is about how I "owe" them a job.
If tomorrow I have no more use for employee X or if my business would be better of without employee X, why would I keep him/her and throw money out the window?
I am not a charity.
Losing institutional knowledge is a cost itself. It can work out better to keep an employee through a temporary downturn to make sure that you have their knowledge when times are better.
Also, businesses are made up of people, and people will interact based on relationships. If you establish that your relationship with your employees is purely transactional where you try to extract as much value as possible from them, don't be surprised when your employees also treat their relationship with you as purely transactional and try to extract as much value as possible from you.