Farah is from Somalia and since 2011 he spends most of his time in Porland, Oregon.
I'm simply saying it's bad for the sport to have the best an an event (5K) racing so sparingly at it. The same applies to any other athlete though.
You could mention Bolt in 100/200 or even Rudisha for skipping out on the DL final in Brussels as well (albeit where he is a long shot) or even Kemboi for only really showing up for 2 races this year (Eugene and Beijing ... may have started more but ran like crap in all of them) but Bolt and Rudisha at last have the excuse of injuries this year.
I just get annoyed at some of the big names racing so sparingly 3 out of every 4 years (or being excused when they do so some of those years) because of Worlds/Olympics. For me at least, putting up good marks and winning competitive races on the circuit, taken as a whole, is as big of a deal as winning medals.