I don't have a problem with supporting them for now. But if it gets to be a 5, 10, 15 year occupation, do we want to be feeding weapons to extend the fighting? Eventually there won't be anything left of the country, or it will more closely resemble Iraq and Afghanistan.
However long it is necessary - and I don't lose sleep over an outcome that is solely the moral responsibility of the occupiers - the latter can always withdraw if they feel that total annihilation is against their ethics. Based on their current course of action, I have some doubts about their sense of ethics holding them back.
Also keep in mind - this is a people who survived the Mongols, Stalin and the Nazis.