Taking away taxes. We love that (as long as we're not the one responsible for defending the country.)
Why detariff? Less deadweight loss. More benefit to society. Less dough for our political bureaucrats to waste. A few companies in China appear to be making amazing electric cars they can sell in the U.S. for $35,000 and make a decent profit; they're a comp to the $55,000 Tesla model. If we tariff those cars with a $20,000 tax, they'll be in price parity with our domestic flavor. If we later go full contact free market...then post-detariff, they'll run the tables with a net-price-to-consumer of $35,000.
In China We Trust(ish).