Except that is not the strategy at all. They actually used a formula that has nothing to do with the countries tariffs, only with how much they import/export from/to the USA. Why else would they put a tariff on an uninhabited island? The penguins surely had a 0% tariff policy with the USA, which according to your logic would mean, that they would get a 0% tariff as per trumps policy. Instead, all tariffs are at least 10%, because if you actually applied the formula to all countries, some would end up with negative tariffs! I strongly recommend this video by Stand-up Maths to understand how the numbers are actually calculated.