and when they took down these "major and global poker sites" did they by any chance ban poker itself?
you see where the flaw in your thought is?

and besides which government are we talking about? bitcoin does not belong to one country to be controlled by one government. it is a global one without any centralized authority to be able to have any effects on it.
if one idiot country government decided to "ban bitcoin" they are just isolating themselves from the rest of the world. other countries have not only adopted bitcoin but also legalized it.