Not having read US media articles on our involvement in Yemen, I am not entirely certain who is the Barry supporting. That being said, the Yemen proxy war has the Saudis (AQAP & other Sunnis) fighting the Iranians (Houthis & other Shias) (http://www.bbc.com/news/world-middle-east-29319423). If we are against AQAP then it explains why when POTUS recently visited Saudi Arabia he was received by the Governor of Riyadh (http://hotair.com/archives/2016/04/20/saudi-arabia-snubs-president-obama-at-the-airport/). Obviously the Saudis were not happy with Barry helping out the Iranians hence the snub at the airport. I say this because usually the media is behind when reporting troop deployments unless the WH wants them to know in advance (i.e. SEALS landing in Somalia under Clinton) yet the Saudis would have likely known of our involvement in Yemen before Barry visited.
Why are our troops helping fight AQAP thus helping the Iranians in Yemen? If the Iranians win, they would have a strategic vantage point to control the Red Sea (and they can already control the Persian Gulf if they wanted).