I have an issue with the idea of "hiding oneself" because it carries a connotation that most or all people are inauthentic, regardless of type, and complete openness and transparency of individuals is preferable. Life is a game. It doesn't mean it's not serious or meaningful. Games played in this world can be extremely dangerous or fun; but they are games none the less. I think people do what they do in life and are who they are, not necessarily because they want to be but because they have to be. And if it requires tailoring one's own style of expression to not draw unwanted/unneeded attention to oneself, to fit the cultural furniture, to carry-on, then fine. I don't see this as dishonest or inauthentic(and especially not in a harmful way), but I see it as necessary for reaching means and ends within established boundaries.
I have come to also expect that hardly anyone will really know who you are, but it is not something particular to being an INFJ - to me this is how life is. Most people do this, whether they are fully aware of it or not, and it makes a lot of sense. What is particular to the INFJ, imo, is the style and the level of cognizance that an INFJ has over these matters. The only types that I have felt totally authentic with, and who I felt totally understood by, are INTPs and INTJs. They actually can see me as I am, and it's totally clear. And it's an impersonal yet mutually understood form of acceptance too. Perhaps I could say INFJ too, but I don't know any other INFJs outside of the forum; but I get that vibe sometimes from other INFJs too. The only difference with INFJs(and sometimes with INTJs) is I get a feeling of not wanting to disturb them, and it's out of respect. [From an outside perspective] INFJs seem so focused on their perspective, and they could be right and often are, that I hesitate to share much because it feels like "they already know". Also, INFJs tend to get lost in the actual words or style being conveyed and can miss the message[and I confess of being guilty of this too]. But I do appreciate their patience and willingness at times to listen(which I'm thinking may be one of their greater strengths). But overall, I believe we are all, more or less, on our own having to navigate through life situations.
Another note: I also believe culture and cultural expectations play a huge role in this authenticity question, and this aspect doesn't get enough consideration, imo. I find that you can say the very same message in a number of different ways, but people will tend to understand it or care to hear it differently depending on the style and context of its delivery. Does changing your mode of expression change who you are or what you are about? Not really, but I think, similar to when translating from one language to another, a lot of the impact, flavor, and richness gets watered down or lost in the process of translation.