This opens up a when can of worms. States can apply taxes to businesses that have no physical location in their state. It is essentially taxing goods transported across state lines.
This is in direct violation of the Constitution, Article 1, Section 9.
No Tax or Duty shall be laid on Articles exported from any State. No Preference shall be given by any Regulation of Commerce or Revenue to the Ports of one State over those of another: nor shall Vessels bound to, or from, one State, be obliged to enter, clear, or pay Duties in another.
And the thing is, they're taxing now based on your residency and the item being transported to it.
What to stop a state now from saying 'well, you went to Florida on vacation. You spent all sorts of money there, brought some stuff back. You must pay state tax on that now that you're back home.'
What's the difference between that an online sales? The only difference is the method of delivery, you instead of UPS or Fed Ex. Residency is still the same, it was still transported to your house.
Or what's to stop a state from collecting tax from online sales from a resident of another state, since part of that transport occurred within the originiating state?
They've opened the door very wide on the issue.