I'm surprised that the Russians were so quick to return. It sounds like they didn't bring much with them, but the fact that their presence is so open is surprising. The Americans and British seem to be taking all lengths possible to stay out of sight. The Afghans have even more reason to hate the Russians, but the Russians just walked into Kabul with a sign that said "here we are!"
Then again, the Russians claim that they aren't there to fight, while the Americans and the British obviously couldn't do that. What I'm really wondering about is not why the Russian troops are there now, but how many more they plan to bring in. It sounds like their numbers are low enough now that they could very believably be exactly what Moscow says they are: security for re-opening the Russian embassy in Kabul and facilitating the delivery of humanitarian aid. If they leave it at that, that would not make them overly welcome, but it would probably at least make them tolerable. On the other hand, it does seem to go against the American conventional wisdom that says the best way to get involved in Afghanistan is to get in, stay mobile, and get out.
I'm not surprised that this development (Russian presence) happened, but I'm surprised that it happened so early. I never thought they would go in in advance of the bulk of the international coalition. Oh well.