Meanwhile fighting “terrorism” has lots of gray, and is notoriously messy.
Khashoggi is very black and white. A US journalist was killed after being lured into a Saudi embassy.
You’re right that the crisis in Yemen is enormous in scale, and it absolutely should be addressed, but the murder of a journalist threatens freedom of information and global accountability and is therefore particularly frightening in that it’s an attack on infrastructure instead of just a person.
"Conflicts gain sustained American attention only when they provide a compelling story line that appeals to both the public and political actors, and for reasons beyond the human toll. That often requires some combination of immediate relevance to American interests, resonance with American political debates or cultural issues, and, perhaps most of all, an emotionally engaging frame of clearly identifiable good guys and bad guys."
https://www.nytimes.com/2016/10/02/world/why-some-wars-like-...
Also, Turkey has been dolling out new bits of information about the ambush regularly, keeping the negative stories rolling.