I do not think Trump attacked GS by withdrawal of invitation. Curry opened his mouth first stating he would not vote to go to the WH. So in my view, it was just fair that Trump not waste time and just withdraw the invitation. I think that to be political regardless of whether or not you like your President, you should still go, and maybe convey your thoughts or feeling rather than react through bitterness
RE: USA. After the politics and the actors, Trump attacks the sportsmen