I guess it's funny sarcasm, though it can have a negative effect on employees. For newcomers, who did not know if this a joke or not, and will be stressed out

I guess it's funny sarcasm, though it can have a negative effect on employees. For newcomers, who did not know if this a joke or not, and will be stressed out to make any mistakes, or either for old staff, who could think that one day it will be no joke and Peter will become jobless.