Encourage people to buy locally? How so?
you propose they undercut someone while having to pay 6% more on taxes?
You want companies not located in a state to unfairly have to suffer loss of buisness and pay money to the state to try and encourage people to buy from stores in the state. That is the same kind of isolationist attitue that people have when they make you pay fees on products imported in order to encourage you to buy locally.
As for you sales tax comment, you obviously don't understand how sales tax works. Companies collect the tax from consumers and then turn it over to the goverment. Retail sales tax is charged only to the end consumer (i.e. you or I going to a store and buying something). Companies don't pay this, so local stores don't suffer more. The reason sites like Amazon and national chains like Walmart can charge lower prices is because they buy in bulk, it has nothing to do with sales tax.
The ONLY people benefitting from charging sales tax to out of state businesses is the state government, that is why they are pushing it so strongly and you rarely, if ever, see local businesses supporting it since they don't really get any benefit.