Do you think the US hadn't already planned to do airstrikes on Yemen? Ansarallah already knew what they were up to. The ships are there to punish Yemen for daring to oppose the genocide in Israel, which they clearly can relate to, having been genocided by the US and Saudis just recently.
Ansarallah clearly stated they would stop if there was a ceasefire in Gaza, and they attacked ships going to Israeli ports. But I guess if they try to blockade Israel, and take seriously their (and every state's) duty under international law to stop genocide, that's bad, but if the US blockades Yemen causing a genocidal famine, that's just dandy?