Active duty military, retirees,and their families are currently eligible for exchange privileges. Expanding this eligibility via online purchases for veterans and their families is not going to be well received by local merchants and major retailers who stand to lose millions. It will likely spawn a debate about automatic collection of sales taxes for all online purchases.
I don’t think that the Congress will go for it.
When you shop at the VA Canteen it is tax free.
Congress doesn’t need to. It’s a matter of policy, not law. That was explained in the article.