Might have been something where they thought that they were OK as long as the sales were out of the area (sort of how Colt can make AR-15s in Connecticut)? It sort of reads as though Optics Planet was taking that position, that as long as they didn't sell >10 round magazines in their town, that they were following the law. Somebody probably told them differently (my guess, the local authorities).
They can move here. Plenty of local IDAs will help them.