In the battle of Amazon vs. Walmart, I have to vote Bezos.
Also, healthy interstate commerce is rather important to the continued success of the Union. WTF, Walmart? If this goes ad absurdum and any jurisdiction can tax any transaction which has an endpoint on their turf, interstate commerce would potentially require tracking compliance with thousands of jurisdictions. "Insane" doesn't begin to cover it.
If I assume that Walmart's strategists are rational, the real intent is probably something like "make Amazon waste money" or "make Amazon get negative PR" or "make Amazon be distracted while we update our business strategies." Probably all of the above, but it's still insane.