Do you propose doing nothing about the people firing rockets at shipping? What about the lives of the sailors on those ships?
Is there some intrinsic right that the rocket-firers are defending that warrants treating them as other than aggressors in this situation?
Why do you call it genocide? Surely if you shoot at ships in international waters, and it is not defence, then you're bringing whatever acts of defence follow on your own head. Acts of defence seem impossible to class as genocide (but I'd like to hear arguments to the contrary if you have them).
OP talked about the millions of potential refugees from climate change we might have. Not the Hoithi rebels firing at international shipping as retaliation of what happens im Gaza.
Regaeding the latter, yes, for bow I think doing nothing militarily is exactly what is needed.
I think you missed who the "them" was in this later part of the thread: not Yemenis attacking civilian shipping, but rather hypothetical future climate refugees from islands that disappear due to sea level rise.