It is getting press of Cheeto idiot starts trade war rather than stating the facts that we are doing a mild version of what's been done to us for years. Aluminum is a hugely manipulated market, I read some stuff years ago about China and Alcoa basically laundering aluminum through Mexico to hide its origin. In general we have been getting rolled on trade for years and if an imperfect messenger there ever was, at least he speaks up.
The other issue to me is national security. Call it a tariff, subsidy, whatever, if you want a country that can go to war, might ought to set aside any Lily white libertarian ideals and make sure you have a domestic steel industry.