Employers save money by convincing the employee that part of their wages are owed by the customer. And as a bonus, when things don't work out, the employee's resentment is directed at the customer instead of the employer. It's brilliant, really.
The divide your enemy strategy works very well, to this day. It takes a fair bit of effort and time to dig around to figure out the reality of what’s really going on.
In general, I’d say this is one large factor as to why we’re losing the class war across all sorts of issues.