It's very provocative but not unreasonable. Do I think it'll start a war? Not unless somebody does something absolutely stupid. I'd be much less concerned if Trump was more intelligent than Kim Jong-Un. We can only hope that, if fireworks start, cooler heads will keep things under control.
I like your analogy of two spoiled brats at a daycare centre. We all knew that Trump would put his foot in something awfully nasty very quickly. I hope it doesn't prove to be something like this.