Same way they do now--it is a business expense and is deducted from gross business income. Somehow, I don't see that changing, and if it does, I predict tenants across the country howling because their rents will go up to pay for increased taxes.
Way too many swamp-dwellers own rental property for that to happen.
Property ownership is far more diverse than Swamp Dwellers. The problem with creating a label is that it starts to be applied thoughtlessly as in your post.
Swamp dwellers would likely be paying higher state taxes than those in other areas but this would affect far more than them.