What if that hadeeth was given ... in taqiyyah?
Jokes aside, it refers to protecting the identity of the Imam and his teachings. Remember, the Abbasids and Ummayads were killing ANYBODY that claimed a rival Imamate/Caliphate, and all Shias regardless of sect (Shias were much more divided then than now). So the concept of hiding your religion, hiding your Imam, hiding the knowledge, etc. was very important for practical purposes. Considering that there is no Imam to protect anymore and that nobody is threatening to kill me for being Shia, taqiyyah is no longer obligatory. In fact, I would say it's haraam unless it's to protect a life or property from injustice, etc.