China doesn't allow their currency to float, they erect barriers to trade and outright block foreign competition, you have NO legal recourse in China if you have a dispute, they apply tariffs, use slave labour (often in the shadows since few operate on the ground there, similar to Stalins gulags which the West didnt know about), they aggressively fund and demand ownership in domestic companies to flood markets and destroy competition until they have a monopoly.
On and on. I haven't even gotten into the IP theft, spying, poisoning of Americans etc.
A 50% tariffs against Chinese products is a gift. If they knew 30 years ago that they would be able to get away with all they have, they would happily trade their situation today from where they were then, even if being hit with a 150% tariff.