The description fits the results, even though the description was not about "this" pendulum. It wasn't even about pendulums, it was about forces and accelerations. Is this not a compelling reason to think the theory is at least robust enough to describe this phenomenon?
Yeah cool, you're making a very clear distinction here between compelling evidence and proof. I think my assumption was that they were ready to prove graviational waves based on the first physical indication they exist. I'm happy that what they've published so far is compelling and worthy of further investigation, but neither would I be surprised if they said the anomoly was caused by lightning or some other totally random factor.