Now for the real reason that frum business owners generally don’t want to hire other frum Yiden.
The owners are afraid that today’s frum employee is tomorrow’s competition. It’s happened countless times that a frum employee will be taught the business and open the same enterprise, even undercutting prices and taking away all the customers.
Every good deed never goes unpunished. And signed agreements aren’t worth the price of the ink used to write it.