The mistake in this assumption is you actually have a choice in the matter.

If you have the choice between buying locally and buying from a certain other country, tariffs can make sense. For example if the other country is trying to get a foothold and dump prices using subsidies. Or the other country has less strict environmental regulations, which allows for cheaper production at the cost of the planet. Then you can put tariffs on those goods, making the local option more viable, which ends up a bit more expensive for the customers but with a better result for your own country in the long run.

HOWEVER the big mistake Trump and his idiots make is there often isn't such a choice. Stuff gets bought from outside the US, because it isn't available in the US. Putting on tariffs raises the prices for the customer, but doesn't really change anything at all other than that. Now you can hope in the long run that leads to products being produced in the US, but that takes decades. The US has been outsourcing manufacturing to the rest of the world since at least the 1970s. Tariffs destroy the economy in months to years and reversing 50 years of outsourcing would take probably 50 years as well. With not just raw materials, but entire supply chains and end-production being done abroad, this isn't really reversible. So this whole gambit is flawed from the get go.

The world has also changed a lot, with such a large population, high speed data connections and a formidable logistics industry, it has become easy for people to get stuff from all over the world. This has lead to each country doing their own thing and doing it well, selling stuff and buying stuff across the world. This global economy isn't something you can just change overnight, nor should we really want to. Isolation isn't the future, cooperation is.

Now this is very simple and broad, there are actually a ton of nuances and tricky subjects surrounding this. But tariffs ain't going to do anything except ruin the economy and the lives of a lot of people.