That's wrong. The crucial part is that it should apply to any random person, not just you. E.g. if it's published in a newspaper, or broadcast on a news channel

That's wrong. The crucial part is that it should apply to any random person, not just you. E.g. if it's published in a newspaper, or broadcast on a news channel, which anybody could watch, then it's public. If somebody told you, and only you, it's not public, because any random person couldn't get the same information.