Should China grant Tibet (and Taiwan for that matter) independance? Of course it should, but it won't happen for decades if not centuries.
It's ironic how people on the other thread talk about injustice. Perhaps those people can enlighten us what the justification in the slave trade was and what the US is now doing to make good that injustice (wiping out third world debt would be a good start)?
The most sensible suggestion I saw was not buying Chinese made products. The economy is the most important thing to China right now so voting with your wallet is the best way to affect the thing it holds most dear.