I am not taking a stance on the law itself, but it is what the current law is. And has been in place for at least a decade in its current form. If it is a serious issue, then people should definitely work to change the law.

But, unless they are the only one available or something, there is nothing in the law saying that specific employee has to keep providing service. The company should make a best effort to remove that employee from contact, without impacting the service of the customer.