Western countries give subsidies to EV buyers, Chinese government gives subsidies to EV manufacturers, including for cars sold overseas. The idea is to drown out competition and then they can drop the subsidies and raise prices.
The tariffs are protection from an unfair strategy and is used in other markets, not just EVs - and against other countries, not just China. The idea is that if another country makes things artificially cheap, you use tariffs to level the playing field.
So yes, tariffs do have a valid use case. Whatever the fuck Trump decided to do with literally all of USA's trading partners is not one of them unless you REALLY want to isolate your own economy for the benefit of literally nobody but a few billionaires. But protecting your own internal industries from unfair competition absolutely is one.