there has to be suspecious activity for ask the identity.i dont know the law completly but even government ask for it and huobi gives, that person can demand his/her secrecy so i dont think we can learn who he/she is.
It seems that some whales are trying to make a scene again but i don't think someone has the right on their mind to send a billion dollar bitcoin on a single exchange. If the government wants the personal information of that person i think it's the work of Huobi to decide whether they have to break the rules against to their customer or to the government.