Trump said he'd be unpredictable and he's being unpredictable. Yet another promise kept. Trump promised he'd put the US first.  He's keeping that promise too. So what's the problem?

The problem is that the German government has been doing whatever it wanted, whenever it wanted, to whomever it wanted.  That little arrangement has come to a crashing halt (thanks to Trump) and the German government doesn't like it.  The German "leaders" can complain and cry all they want but their free ride is over for good.