Blizzard and the consumer are both obligated to follow relevant tax laws. In NJ (apparently), there are no sales taxes for these types of purchases. Legally, Blizzard does not have to charge a sales tax for purchasers who live in NJ. However, if you live outside NJ, you must pay a sales tax, which allows Blizzard to collect on that tax. If you lie and report that you are in NJ, then you are evading taxes because you should have paid that tax, not Blizzard.

Basically, you should look at who's being deceptive. In this case, Blizzard is a large enough company where plausible deniability is 100% a thing. They set up a system where, assuming the customer is honest, everything gets paid to everyone who need to be paid. You, as the customer, are purposely deceiving Blizzard (and by extension, the US government) to avoid paying a tax that you are legally obligated to pay.

It's like arguing that the gun company should be punished when one of their guns is used in a homicide. (Let's ignore the fact that that has actually been argued with some degree of success for some reason...)