If you did business with a friend and you purchased $5 worth of stuff yet he turned around and only bought $1 worth from you, his buying power would increase exponentially whereas yours begins to seep away. It's easy to see that you’d be better off cutting off doing business with your friend and try to sell your products to someone else. The less business we do with China, in the end, the better off we are even though it might hurt U.S. suppliers temporarily.
By the way, Trump is only asking for a comparable deal not in any way is he wanting to take advantage of China like they'd done us. Why liberals don't get all this, I don't have a clue.