The playing field is level already, a state determines what its tax is on citizens of that state. There is a very basic principle here, the citizen is responsible for his own actions to his own government. If I sell something, I am responsible for my sales taxes. If I buy something, I am responsible for the use taxes. If this were passed, then I become responsible for collecting sales taxes owed to a government where I am not represented.
If I make a purchase from someone in another state and they are not subject to taxation by my state and the sale is still considered a taxable transaction by my state, it is called a use tax but must be paid by me. (This is often ignored, but NY, IL and CA are trying hard to make sure their citizens pay taxes on sales where the seller is not subject to their taxes.) I am represented in the government I pay the use tax to.
As a resident of IL, when I purchase a delivery truck from someone in NH, I should pay IL the appropriate use tax.
As a resident of NH, when I sell a delivery truck to someone in IL, why should I pay for the government of IL? I don't like the government of IL; I'm not represented by the government of IL; I choose not to live in IL. I certainly have no interest in collecting their taxes for them.
NH and AK don't seem to have many representatives suggesting that their citizens should have to collect taxes to pay to other states. My own (actual) state has a higher tax rate than IL but I don't think citizens of other states should help us collect our taxes. I'm not thrilled to pay my state's sales tax but I accept it without rancor. I far prefer it to paying my income taxes and can only imagine how much bile I would feel collecting taxes of IL, CA or NY where, as was said previously, they don't let me vote in their elections.