The opening of markets falls under the fairness principle. If other countries open their markets to your products, then you have to return the favor; otherwise, you're not playing by the rules.
「開放市場」是在「公平」的原則下，演繹出來的另一條國際遊戲規則﹘﹘別的國家對你開放市場，你當然得同等回報，否則大家都關起門來，國際遊戲就玩不成了。