If you read it you'll see he's being tongue in cheek.
Facebook conduct job interviews in a hot tub? That could feel a little awkward.. especially since programmers not generally known for body confidence.
You missed the bit that says
> "[Ed: This is completely untrue, in case this fantastical point seems plausible at first. I installed a hot tub (non-functioning) as a conference room in Facebook Seattle. Interviews are never done in them.]"