Houthi attacks on international trade are in fact a direct attack on the West by an arrogant and self-confident Iran. Hamas, Hezbollah and the Islamic Jihad are arms of an octopus that if you want to neutralize, you have to hit it itself.
This attack against Americans is an attempt by the Islamic Republic to test whether the West in general, and the United States in particular, are capable of responding. Iran's goal is to destroy Western culture at any cost. The Revolutionary Guards' efforts are part of their broader strategy to weaken the entire West.