Why is the Millworks customers allowed to park in the Broad street parking lots and the Market customers can not park in the Millworks lot?

I believe it would be because Millworks parking is a private lot and the spaces around the Market are public street parking.

Patience is a virtue when it comes to parking at the market

Because the Millworks is a private business with its own parking. Its customers should not have to complete with customers from somewhere else. The Broad Street Market is owned by the city, and therefore its parking is public.

They're not supposed to