First the tweet. So while I agree with going after Amazon for the tax shelter portion, blaming Amazon for using the USPS when the USPS pricing and cost model is the problem is just plain stupid.
well some states which determined that amazon has presence in their states impose sales tax on purchases on amazon (NY for example) but anyway it should not be trump's problem since we do not have federal sales tax, (or rescind the rule when all internet is exempt from taxes) as for usps i agree with u as for trump's concern about small business that can not compete with amazon , he forgot (if ever knew) first rule of capitalism - creative destruction