Amazon recently took it upon themselves to start charging tax in a number of states that they don't have warehouses in. Even less reason to shop there now. I go for price, not who can get it to me faster. Granted good to see they dropped the price down, but they have and more stuff behind the Prime paywall - so if you order 1 item, they won't actually ship it to you until you order other things....
Sales taxes are right to pay in every way. Why should some company shipping from out of state get a competitive advantage over another company that has stores in your state, employing people in your state, paying property taxes in your state, generating income taxes from those employees in your state, etc.?
Answer: there is no reason. It's a historical aberration from 'let's help the internet get off the ground' and the practical difficulties collecting the tax.
Those taxes go for extremely helpful and needed things. They pay for the medical care for the less fortunate. They pay for the state services that do a lot for the public. They pay for a lot of good programs. I think it's basically short-sighted, destructive selfishness that leads people to say "no way I'm paying sales tax on my new big screen tv". Pay it and be proud as a citizen.