Its hard to be sure. Trump is very ignorant on many things, but he also is totally willing to feign ignorance to push a narrative. I have a really hard time believing that at this stage in his life and political career, he really doesnt understand trade deficits or how tariffs work. I think rather, he knows many Americans dont understand it, and its just convenient language to use in place of ulterior motives. One thing Trump does understand is the importance of a narrative. If he wants to do X for some shitty, self-serving Z reason, he will give Y reason instead. Y may have nothing to do with X, Y might be a complete made up lie, but he will keep saying Y on repeat, over and over. Fox News will gleefully repeat Y, as will the entire conservative new media apparatus like podcasters and surely Joe Rogan will bring on guests to talk about Y, while he crafts some viral moment where hes just blown away that no one ever thought about Y and why dont the left care about Y and just let Trump do X? You can apply this over and over again to his entire presidency for the next 4 years and possibly beyond.