If you're heading into Ros Dov in the middle of a wintery night, you know very well that diverting to any of the nearby airports will induce massive amounts of operational headache. It will basically be you and your crew, trying to sort out everything for yourself and your passengers. In the middle of very, very rural Russia, that is a daunting task which is bound to result in passenger complaints and, quite possibly, a social shyte storm when the inevitable happens, and you find yourself, your crew and passengers stranded onboard an increasingly frigid 737.
Those thoughts are bound to enter the mind of a commander, and is very likely one of the reasons why he decided to press on with the landing - even after a two hour hold and reports of WHSR.