How could interviewing be anything but a game? I understand some wouldn't want it spoken of however.

Part of it is, indeed, talking about unspoken rules. But part of it is that the hiring managers and CEOs are humans like everyone else - some may have ego issues, or buy a little too much into their company's branding.

Exactly this. The first rule of fight club is don't talk about fight club.

What surprises me more: Many people don't think interviewing is a game. They think it is straightforward and "rules-based". I guess those same people also believe PR. :)

Or want the world to be fair and honest, and - per the well-known saying - they are themselves the change they want to see.