To be fair, I got the mail too and it has a link to the OW benefits page, which states:

oneworld lounges

If your oneworld frequent flyer tier status is Emerald or Sapphire, or you are travelling in a First or Business Class cabin on any oneworld member airline, you can access more than 600 airport lounges throughout the world. Relax or catch up with work in comfort and style before departure, regardless of which oneworld member airline you choose to fly with.

So... typo. Another day another BA SNAFU, nothing to see here folks, move along...