While theoretically bitcoin should be preferable to usd for them, too much of the bitcoin infrastructure is US based, so one can understand their fears. China is a significant bitcoin player already, and could completely reverse that perception, but the Chinese lawmakers are too afraid of losing control over their currency (and the political/economical power it gives them) to allow bitcoin to flourish as it could in China.

So yes, in many ways brics have good reason to consider bitcoin as being a Trojan horse of free economy. Terrorists are or should be afraid of bitcoin for similar reasons.

IMHO Bitcoin is to currency what the BBC world news is to information: it empowers people and weakens dictatorships. Like the BBC it has it's own agenda, and it won't be enough to change the world or topple bad governments on its own, but it's a step.