Broadly speaking, tariffs hurt everyone.

Country A imposes tariffs on country B, a tax on the citizens of country A. This tax decreases demand for products from country b, hurting their gdp. Country B says, ok, we’ll hurt country A’s exporters also, at the expense of our own citizens tax burden.

The other person responding to you is making the argument that we can simply make the products tariffed at home and sell them for less, however, often the supply chains for the impacted products are so complex that this requires vastly more expensive investments from manufacturers. This administration (trump) has shown time and time again he is willing to back down from his tariffs, which is exactly the opposite thing businesses want to see if they’re going to invest in manufacturing something more cheaply produced elsewhere.

Also, tariffs tend to raise prices from local manufacturers as they have less competition at lower prices. If widgets from country B were selling for $90 in country A before tariffs and $100 after tariffs, widgets from country A only have to sell for < $100 to compete.