China has been one of the worst offenders when it comes to illegal trade practices, which includes but are not limited to large scale currency manipulation
U.S. files WTO complaints against EU, China, Canada for responding to steel tariff
U.S. files WTO complaints against EU, China, Canada for responding to steel tariffs - MarketWatch
They've been hoarding USD for years which drives up the value of the dollar making US export's less competitive.
China has also been dumping Govt subsidized Chinese steel and aluminum for years.
Our European trading partner's are no better.
Germany exploits the Euro's fixed value accross all EU member Nation's to maintain a trade surplus and an advantage over their trading partner's.
Since the Euro's value is fixed, Germany can run perpetual trade surpluses without making their exports less competitive, and they've been doing this for years
I'm no huge Trump supporter, but at least he's attempting to address this issue.
Most people that criticize Trump for taking on our trading partner's do it because they hate Trump and or are still sore over the results of the 2016 election.
They usually have no clue about trade or the multiple trade violation's that the US has lodged with the WTO over the years