Of course it is. No one controls it and it can't be destroyed. The concentration of hash rate in one country is something that might need to be addressed in the future but the currency functions just fine.
I cannot agree. This time "People in that room represented over 50% of the worlds bitcoin miner production". How about next time? 75%?
If "People in that room" make a decision to do short for bitcoin, and they may hold short on exchanges, what can we do?
Like I said the concentration of hashing power in one country might be something that needs to be addressed but mining is only half the game. Also they can't really do much with it other than mine coins. It would take a huge effort to coordinate them to do something nefarious.
Chinese exchanges have been effecting price for a while now. If they all decide to short the price would adjust. To damage bit coin runs counter to their interests.
I'm pretty sure if someone asked Satoshi 4-5 years ago if it would be ok to have meetings of over half the hash power of the network he would say that he never intended such things and that it's a problem that should be solved.
Hell, he didn't even foresee mining pools from what I remember. His original intention was everyone using their CPU and having the client running to generate coins.