I highly appreciate the model of FB. It allows you to express yourself. But I personally think the Pakistani government is not right in outrightly banning FB. The cartoons about Muhammad (PBUH) were probably devised by some racist group, not by facebook itself. FB is just a platform to socialize and express your views, nothing more. And it is normal that different people will have different views about something. Why punish the whole website just for a few unscrupulous people who creates such racist groups...? Look at the good side! Friends and colleagues are able to socialize through it from great distances. Business is so easier.
And yes, there is a function to report such hate groups, but its practically impossible for FB employees to remove ALL hate groups. Even "hate groups" are a way to express yourself - a means of freedom of speech. If hate groups are removed, more will be created. And more and more. Practically impossible, and will undermine the ultimate purpose of facebook itself.