I guess you are talking about two issues:
BS international regulations embedded in trade agreements
currency games/undercutting competition games
No 1, is a compelling reason to not have trade agreements, and just let the actors in your economy trade freely, but not a reason to pile on more state bullshit to compensate for the fact that the state already has a ton of bullshit that it can't seem to deal with
No 2, this is basically a case of an opposing state actor thinking that it can allocate capital and production more efficiently in its economy than the private sector can, but they can't. Whatever games they play to over assist one sector must come at a loss of somewhere else. Maybe they make trade competitive by watering down their money, but that would come at the expense of the currency and savers in their economy. Maybe they will help the steel mill, and subsidize steel production, but that might come at the expense of food production or the high tech sector. In the end, whatever time, energy, money, human capital, and resources they put into one area must come at the expense of something else.
Of course, if China subsidizes steel, a steel producer in the USA may not be happy, but millions of customers getting cheap metal to build things would be. But in practice, a healthy capitalist economy can take back steel production at any time foreign manipulation stops.
In sum, just because one country is dumb enough to sell us stuff under cost, doesn't mean we should be dumb enough to not let our people get a good deal. Though I suppose if we manipulate our trade just enough to undo state manipulation of their trade, the damage would be limited, but once our state starts down that path, I doubt they have the muster to keep out state interference from growing out of control.