lol, ok, I'll bite. Other than one side might try to change the rules; why should I believe is free trade is no longer universally good? What is the specific argument?
Because if the argument is that one side might impose taxes, duh? But that's no longer free trade is it?
If both sides were willing to play fair, why wouldn't that be better? And why shouldn't we all be trying to "encourage" everyone to play fair?
Japan closed itself off from the world for centuries during the Edo period. One could say that they suffered economically due to that, but on the other hand, they ended up creating one of the more unique cultures in the world, developing in ways very different from others. It's an interesting kind of diversity.
Or .. lets say due to weather, your farmers can not grow enough oranges or some fruit which drives up local prices. Should only the richest people in your country get to eat fruits ?
Or you discover lithium deposits that your national industry can not use . Should you let that just sit there knowing it could make your province prosperous if traded.