Yes, you and everyone else should be opposed to targeted tariffs levied by a president in time of peace. Targeted tariffs create a hostile environment between the two nations. With talks between the US and NK coming up in a month we need China's support. China is NK's oldest and strongest ally and their major trading partner. China can turn the bargaining table upside down on Trump with a phone call; not a good time to start a trade war with China.
Trump's tariff are being levied by executive order and will last only as long as he is in office and Republicans maintain control of congress. The tariffs are not popular with either democrats or republicans in congress. If Democrats are successful in the fall, congress could easily stop Trump. Since the executive order will expire when Trump leaves office, the tariffs could expire in 2 years or sooner. In other words, the tariffs are temporary with an uncertain future. Neither Chinese nor American businesses will change much at all. Americans will pay more for goods from China and the Chinese will pay more for American goods.
The Trump plan is obvious. At some time in the near future, maybe shortly before or after the tariffs are scheduled to go into effect, Trump will announce a major breakthrough in his negotiations with China. He'll regurgitate his interpretation Xi Jinping comments so they appear to be a great victory, praise China and his staff for the wonder work they have done and announce a new era in US China relations. Of course, it will all be BS.
1. We are not in a
"time of peace" We have been in a time of war (economic) upon us by Mexico, for 70 years, and by China, since Bush 41 gave them unrestricted access to our huge/valuable market, without reciprocation.
2. There has BEEN a
"hostile environment" for many decades, caused by hostility of countries (primarily China and Mexico) against us, engaging in international burglary of our economy (remittances$$, unfair trade balance, devaluation, etc)
3. We can get China's support more by playing our high cards (our massive market & tariffs) and being strong, much more than being weak.
4. Got a link for >>
"The tariffs are not popular with either democrats or republicans in congress." ? 
5. How is it possible that, as you say >>
"Neither Chinese nor American businesses will change much at all." Do you think Trump is going to place tariffs that are too small to have any impact ?
Tariffs at US ports are going to increase shipping costs to make those goods
not economical to ship, and force the American companies to return to the US. That's the whole idea. Did you miss the 2016 campaign ?
6. No, Americans will not pay more for goods from China, because they won't be goods from China, they'll be goods Made in USA again. Those that remain in China will not be able to raise prices without triggering devastating SALES$$ reductions.
7. Nothing that Trump is doing is
"BS". Nor is it the slightest bit difficult to ascertain. He is simply undoing the damage done by 4 moron US presidents who for 30 years, have inexplicably given China unrestricted access to our massive and highly valuable MARKET, which China needs, with no reciprocation.
If he didn't do what he's doing, he would be a moron just like they were.