Something does not add up here.
You're forgetting how they teach math in the Glorious People's Republic of California: Your bank account contains your money. According to California, your money is their money, so by the
Transitive Property, your bank account contains their money.
The reason CA gets away with this extra tax is because they aren't calling it sales tax; it is "use tax", which is a form of property tax.
According to the State Board of Equalization, " ..if sales tax would apply when you buy physical merchandise in California, use tax applies when you make a similar purchase without tax from a business located outside the state." Since California can't charge you the full amount (they don't want to tax you twice - that would be illegal!), so they charge you the difference between California's use tax and the tax you paid when you bought it, unless of course, you paid more taxes when you bought it.