That is precisely it. We're arguing semantics and no, it's not the "APA National Amateur Title". If it were, I'd have less of a gripe. It's the "US Amateur National Championships". What's more, the stream makes constant reference to how these players are the very best amateurs in the country. The truth is, some may be but not all.
In regards to the US Open, you're right. If players fail to show-up, it detracts from the title but then, they're not billing the US Open winner as America's best pool player, are they? They just say he's the US Open winner.