Imagine what would happen if it was found out that Rumsfeld was secretly funding a private army that went around the world killing innocent people. I venture a guess that there would not be a country that would not stand against us, and there are countries that would take the opportunity to unleash their weapons of mass destruction with impunity from international scorn.
I don't personally see why the reaction against Afghanistan should be any different.
It is actually worse than as you state. The way I see it the Taliban brought in OBL BECAUSE he was the world's leading terorist.
The Taliban had prior knowledge of his activity, and condoned it. They are not only accessories after the fact, but before the fact as well.