He doesn't understand anything about basic economics and trade relationships. He thinks America's trade deficit means America is "losing". He see everything though the prism of politics, in how tariffs can benefit him, not how it impacts America on the whole.
His tariffs, like all his other policies, is not therefore based on facts but only on how it will impact his political fortunes.
Bottom line, the market euphoria over the "trace" in the trade war is naive and unwarranted, the two sides are fundamentally stuck on some basic non-negotiable issues. Don't expect the trade war to end anytime soon.