Retailers, on-line or otherwise, have to pay sales tax on sales within a state where they have a physical presence. That's the way it is. The problem in this case is that CT wants sales tax on a sale that was referred by an affiliate... Even when the retailer (Amazon) and the customer are both not located in CT. In states that charge sales tax, most (all?) charge "use tax" of the same amount as sales tax, on items shipped to them from an out-of-state retailer that did not charge sales tax. Retailer customers almost never pay it, probably don't know it exists. Sates usually don't go after the tax for consumers, but they do go after businesses for it (at least they do in CA) presumably because the amount of tax is potentially much higher.

In other words, technically, you have to pay sales tax when you buy something, and if you don't then you're supposed to pay the equivalent amount in "use tax". In this case, CT is trying to wedge in there and get tax when neither the buyer or the retailer are in CT.

It's not a business killer for Amazon to charge and pay the taxes for every state. Many on-line retailers do. There is software and subscription services to keep billing systems up to date with current tax tables. But, who pays sales/use tax on what when a guy in CA buys something from Amazon that was referred by a CT affiliate? What about when someone in a state where Amazon has no physical presence buys from Amazon through a CT affiliate? My brain hurts and I suspect someone's getting screwed.