I'd also like to point out that, in this case, it ain't RAI (since we have a tweet from a developer stating they'd apply Dueling to a thrown weapon, if it was thrown from one hand), nor Rules As Commonly Applied (as evidenced by the majority of people here supporting Dueling working with thrown weapons) nor Rules As Commonly Applied In AL (since one of the other posters generously decided to go to some AL Discord servers and they agreed with the dev tweet).

There's no inherent superiority to RAW, even when it is on your side. This isn't a wargame where people are directly competing-it's a TTRPG, where everyone is playing together. It's good common ground to discuss on forums like this, but actually hewing to the RAW over RAF is to the detriment of a game. Moreover, 5E was not designed to be read like a computer-it's meant to read in common parlance. So, while a certain reading of RAW can result in Dueling not applying to a one-handed thrown weapon, the common interpretation (even to those not familiar with D&D) would generally be that, if you threw a weapon that was wielded in one hand, you'd get the Dueling bonus.