Since this looks like another Middle Eastern sectarian war and there's no real 'good guys', I suppose the West will try to please its allies by towing their line. Probably geopolitics as well with the Saudis backing the Sunni Yemenis and Iran backing the Shia. I would have thought Iran would make a better ally than Saudi Arabia, Iran is less extreme in its fundamentalism and has a relatively strong civil society/general roots for democracy and Westernisation.