Foreign taxes are effectively a business expense for corporations in the US, since the foreign tax credit allows them to not pay taxes on the taxes paid to foreign countries.

I think this makes sense. If I live in the US and make some product and sell it in Germany, then whatever profit I bring home from Germany (less German taxes) is still an income that was effectively earned in the US, since I am living and working here. The business transactions occurred in Germany, but the income was 'earned' by my labor in the US.

From this point of view, a territorial tax system is a subsidy designed to make goods more competitive in foreign markets. (Since I don't have to pay taxes on foreign profits, I can lower the price I charge overseas.)