yes, but public opinion is of huge importance in unbalanced conflict such as this (where one side is vastly stronger). Look at how much its working to the benefit of Palestinians. You don't see any "Freedom for Chechnya" activists running around, do you?
The thing to remember is - well two things actually - is that, first of all, Chechen militants don't really have any great power backing them up, like the NVA had in Vietnam. America, the EU and all the rest are more than happy to look the other way if it means maintaining good relations with Russia. And the second thing is that things are about as bad for the Chechens as they're likely of get. Every crime, every humiliation, every slap in the face and kick in the ass that it is possible to have happen to you, chances are its already happened. Which means there is no longer the shock value of "the Russians killed by brother, I'm going to go join the rebels". Anyone who is likely to stand up and fight has, after a decade of occupation, already done so.
Put these two together, and you come to the conclusion that the Chechen militants are not likely to win this thing by a war of attrition. And what I am assuming is that whoever is running the show is aware of this fact. And even if it is possible to force out the Russians by attacking the civilian population until they simply stop thinking its worth it, how long will that take? 10 years, 20 years? More?
You may point to al Queda and 9/11, but thats not really the same situation. First of all, and no offence intended, Americans are more sqeamish towards casualties. And secondly, al Qeuda not only has vast funding, but they have a wide network of alliances and like-minded organizations all across the Middle-East. They can actually stand up to the Americans militarily and have a chance of forcing them out. Afganistan is partly (dare I say mostly) under rebel control. And Iraq isn't going to well, as anyone can see.
So, whether you agree or disagree with the Chechen rebels, it simply doesn't make sense to do this, from a rationl self-interest point of view. Unless there's something I'm missing, and there is an excellent possibility that there is, no one with half a brain would do what was done at that Russian school.