Because getting into a tariff-based trade war (especially the "reciprocal tariffs" which aren't tariffs at all, but just some made up term for trade deficits) is just stupid and everyone knows that; the clip below from the Economist summarizes much of this, well. Sure, maybe Trump is playing some high level negotiation game which will eventually settle at much lower tariff rates than those being proposed now (with the US hopefully gaining some advantages over the current state) and the markets will then go right back up, but I'm not so sure, as he has been on record for 40+ years as loving tariffs and looking back fondly on the 1890s when tariffs were high and there was no income tax. But things back then weren't nearly as rosy as he thinks and the world has changed hugely since then; see the 2nd link.
I'm not an economist or trader, which is why I'll stay very conservatively invested, but I do know that these tariff-taxes are going to hurt regular folks a lot, especially small business (as Jason Furman, former Council of Economic Advisers chair just said on CNBC) and especially if a serious trade war with China really does happen. It's all just so foolish, especially given how strong our globalization, free-trade-based economy has been for the last 30+ years and especially the last 10 under both Trump and Biden (despite the COVID blip) - I just don't understand why he'd screw with success other than he can and enjoys wielding power.
https://www.pbs.org/newshour/politi...h-saw-industrial-growth-together-with-poverty