The interesting part here is that this is just a direct "cost savings" to FB. These workers are already being paid X due to their current location. So from FB

The interesting part here is that this is just a direct "cost savings" to FB. These workers are already being paid X due to their current location. So from FB's balance sheet perspective, there is no change to continue to pay them X if they move to a lower cost of living area. Telling them they will now receive Y (Y < X) because they move is going to discourage them from moving, and appears optics wise as FB looking to squeeze their employees as much as they can.