That is not what I said. I said:
if they don't, the female can die
https://en.wikipedia.org/wiki/Ferret_health#Neutering
A female that does not mate can die of aplastic anemia
It has to do with human interference.
Ferrets have survived for a millennia, on several continents, despite human interference.
They were here before us and they will be here after us.
That changes neither the facts of their biology nor the responsibility owners have.
Vermin are among ferrets' prey.
Where did you hear female ferrets can die during mating?