US Navy seal attack in Yemen

There is a wretched civil war in Yemen. In this war, Saudi Arabians have sent in their forces against one side of this civil war, principally the Houthis.

The US is an Ocean plus a continent+ away from the Yemen. What on earth is its business in a civil war.

But, by its sovereign power it feels it must intervene. The question is what is the desired final outcome to do such thing? If you cannot answer this question, then this insertion of Navy seals with the cost of one US sailor's life is simply UNJUSTIFIED:

https://www.washingtonpost.com/world/national-security/us-acknowledges-civilian-deaths-in-trump-authorized-yemen-raid/2017/02/01/e1f56c3c-e8e0-11e6-80c2-30e57e57e05d_story.html?hpid=hp_hp-more-top-stories_usyemen916pm%3Ahomepage%2Fstory&utm_term=.23b528f7fe23