What causes the US media obsession with tariffs; The EU and others have charged tariffs on US stuff forever? The EU has about a 50% tariff on US beef and higher tariffs on US liquor (typical EU bureaucracy has many categories and quotas, so a single number is impossible). So why is a relatively low US tariff on 2 materials, (the EU has tariffs on about 100 materials from the US) make so much news time?
Nations frequently have tariffs between each other. However, the trend since WW2 has been fewer tariffs and other trade barriers. For example, even recently the EU has significantly reduced tariffs.

Likewise, the US has also both practiced and preached free trade, reducing tariff rates. 

Economists have strong consensus that tariffs are bad. This isn't dependent on political leanings, it has wide agreement. "The economics profession continues to show a consensus in favor of unfettered international trade, as 83 percent agree and only 10 percent disagree that the United States should eliminate remaining tariffs and other barriers." 

The reason the new tariffs are reported by the US media are because they are a new policy change which oppose the existing trends and expert opinion, although they do have public suport