Virtually everything Trump has said over the past week as he continues to attack Amazon has been wrong, but the truth is not important to him.
In this case it's possible he may actually be aware that Amazon is not costing the Postal Service money, or that Amazon does collect sales tax, but it doesn't matter. According to Vanity Fair, Trump is on a mission to attack CEO Jeff Bezos because he owns the Washington Post and the Post has not deferred to Trump as much as the New York Times has.
Now, according to four sources close to the White House, Trump is discussing ways to escalate his Twitter attacks on Amazon to further damage the company. “He’s off the hook on this. It’s war,” one source told me. “He gets obsessed with something, and now he’s obsessed with Bezos,” said another source. “Trump is like, how can I fuck with him?”
Trump is reportedly considering ways to attack Amazon, from canceling their federal contracts with the military to ordering the Postal Service to renegotiate their contract.
I'd say the likelihood of these things actually happening is slim because Amazon could sue the federal government for breach of contract but, in any case, I believe Amazon shareholders should consider filing a lawsuit against Trump before he escalates.
Trump's attack have already caused losses for company shareholders and it's clear he's doing it for personal reasons. This isn't about policy. This is about Trump's hatred of an independent media. Trump is committing securities fraud with the goal of intimidating Jeff Bezos, but I doubt Bezos is afraid of him.