Strategic investment my guess. You don’t want your allies succumbing to your enemy. Not sure how funding is decided on, probably based on % of GDP and US has highest GDP.
Discussion
EU countries like Germany are buying energy from “the enemy” so the whole narrative makes no sense. NATO countries are supposed to contribute 2% of GDP to NATO which countries are not doing so the American tax payer has to supplement their lack of contribution while those countries purchase energy from the “enemy”. Makes zero sense. Seems like a scam.
Keeping your enemies dependent on you is a strategic advantage. Cutting a nation off will only force them to innovate and not be dependent on you.