They're conservative to their core and that means rejecting the progressive policies that give "blue" states advantages over these other places. And so it's just natural that they'd also oppose this progressive policy too. The establishment in these states have convinced the poor and middle-class that the status quo is the only quo for them, and these people will fight for their right to be kept down.
They believe they have a god given right to be screwed over by the powerful and to screw over those less powerful than themselves, and they'll be damned if they let anyone take that freedom away. And if that means that they get paid sucky wages and aren't offered real insurance by their employers in order to ensure that the powerful stay powerful, that's what has to happen; even if these policies harm the overall economy. It's better for a few ships to do good in low tide than to allow a high tide to improve everyone's ship.