But more directly it's hard because of the attempt by the Chinese authorities to lock down every possible information source. It will come as no surprise that I don't think closing Tibet off from the rest of the world is a good idea - or indeed a good sign.
If the Chinese authorities were telling the truth about the violence allegedly carried out by Tibetans, then having external and independent observers is precisely what they would want. The fact that they don't means that their own stories must be viewed with suspicion, especially since they flatly contradict videos and images that have been smuggled out. Moreover, the fact that it won't even trust its own people - who seem inclined to condemn the Tibetans as "ungrateful" anyway - to judge events, and has blocked practically all external news sources, is yet more evidence that there is a massive coverup underway.