Coming out isn’t what it used to be. Literally, “coming out” has a rich history of different meanings. Originally it referred to young women coming of age into high society. It had a derivative meaning within gay subcultures of the late 19th and early 20th centuries.
But in the 1970s, “coming out” started to mean revealing yourself to the general public. “Coming out” was contrasted with “being in the closet”. In the 1970s, coming out was advocated as a form of political action. You can see this, for instance, in many speeches by Harvey Milk. Here’s a line from the Gay Freedom Day Speech in 1978:
Gay people, we will not win our rights by staying quietly in our closets…we are coming out! We are coming out to fight the lies, the myths, the distortions! We are coming out to tell the truth about gays!