Microsoft is a US company but Xbox is an imported product, being manufactured in China. Therefore it was subject to the tariffs.
Let me ask you a question.
Say you export bananas to the European Union. Then the people in the EU vote to prioritize Europe above every other country (MEGA) and thanks to them you suddenly have to pay import tariffs on every banana. You are forced to raise sales prices to compensate which reduces the number of sales and lowers your turnover. Now it turns out the tariffs were unlawful and you get money back from the EU. Would you feel that that money belongs to the people in the EU?