He's doing that because he's monitoring the rate of fermentation from an innoculated culture to a non-innoculated culture. It's not because he doesn't know how to use an airlock.

If you read the thread it's actually both. He doesn't realize he should put liquid in the airlock and he's monitoring the gas. The course of the comments is most of the comedy. It takes quite a while before someone points out there isn't any water and then someone FINALLY writes "are those CONDOMS".

If that's the case I'm sorry, But why not just strap the "wiener keeper cleaner" to the jug?