There really are only two choices for me.
Either this was typical Trump hyperbole...or he was threatened into wimping out....
One other possibility that that he really believed General Mac and crew had super duper secret sources that he didnt have and eventually found out it was not true.
Trump's a deal maker. He's not going to waste political or financial capital when he thinks he's not going to win in a given battle.
He waits and keeps his powder dry.
If Trump was willing to play in mob-controlled areas of business (construction/labor/bldg materials in Manhattan) when he was just a kid, he's not going to "wimp out" when threatened by some cheap DC bums. He'll wait.