When President Obama privately asked Rick Wagoner to resign from GM, do you think that spared him from embarrassment or feeling bullied? There was absolutely no need for Rick Wagoner to have to resign, but the Obama administration needed a blood sacrifice to sell a bailout. A 30 year career at GM ended in disgrace because the government couldn’t trust him to turn around GM, even though he was a popular CEO.
But you’re right, the Obama administration didn’t publicly bully him, just privately did so. I don’t see one method as better than the other, there’s a use for either but they both have the same goals.
Fortunate for Tan, a lot of people don’t like Trump and he’ll probably gain more public support and potentially stay on as CEO. This is certainly where this backfires on Trump as his method of publicly shooting from the hip doesn’t always work. Tan becomes the target of the day, forgotten about a week later. This is where Trump diplomacy could work better through private methods, but we also don’t know if that’s been tried. Quite honestly, I think he just had somebody whispering in his ear and he just decided to tweet it.