Bad management, agreed—but because policies like this make it cheaper to go with the cheap temporary import. And if others in your industry are going with that option it is hard not to follow suit if you want to stay in business.
This is all bought off bad policy that employers have lobbied and bribed our pols to give them.
Problem is temporary quickly turns into permanent when they forget to leave. Add a few anchor babies and there’s no getting rid of them - IF anyone bothers to look into their records.