If I've got this straight..
A guy walks into a store in Santa Monica and buys a receiver and pays 9.25% sales tax. If he went a few blocks to a store in Orange county he might pay 7.75%. Doesn't matter to the store what the guys address is - they charge everyone who comes in the same rate.
If he buys the receiver online, the dealer needs to run some cool software that's provided by the States to calculate which of the hundreds of different rates they might need to charge based on where he lives.
So, in my State, where there is no sales tax, the online retailers need to calculate and collect taxes for every other State (but three, I think) for no good reason other than someone's view of "Fair". They don't get anything in return, and the taxes collected don't benefit anyone in his State. Currently, they don't collect any taxes from anyone here, and even the guy who who drives from California to buy that receiver doesn't pay any taxes if he walks in the door - only if he buy's it online. Nothing but more work for businesses.
If "they" really want to give some appearance of being "Fair", they could just have the online retailers collect the same taxes from their sales that the brick and mortar store next door does - Regardless of where the guy who bought it lives. The sellers State gets the money, the store owner next door is not at a pricing disadvantage because of taxes, and we don't need any fancy software or new national bureaucracy to monitor all this.
It'll never happen that way though. Seems like California is losing quite a few businesses for various reasons - They wouldn't like it if they lost online retailers to Montana, New Hampshire and Oregon so their prices to the customer could be 9.25% less.