Sorry guys but if we're going by the book the thrown property does not a ranged weapon make.
Here's the problem. The rules are written in English. When someone says "that guy attacked me with a ranged weapon" and you weren't playing D&D, you'd think that would include anything at all that could be thrown, launched or shot at you. So, when you read a book that says "when you attack with a ranged weapon", you'd likely think that likewise includes anything that was not used in melee. The book is still vague enough to rule either way. After all, how does one make a ranged attack with a melee weapon if a melee weapon can only attack things within 5 feet of you, like the rules say. That's an impossibility. It has to, at least temporarily, become a ranged weapon for the duration of the attack since the rules say only ranged weapons can attack at a range further than 5 feet(and thrown weapons let you make a ranged attack with the weapon. But once again, if a weapon is used at range, it is logically a ranged weapon).
Yes, things like dagger and the like are in a table that says "Melee Weapons" and they are separate from another part of the same chart that says "Ranged Weapons". If the rules are referring to the classification in that table and nothing else, then it is completely clear. But if at any point we assume the rules MIGHT be referring to the English definition of "Ranged" or "Ranged Weapon" instead of a definition made up expressly for D&D, then things get a little hazy.
Although, yes, the Sage is looking at the exact same thing you are when he made his ruling that Melee Weapons with the Thrown property aren't "ranged weapons". Which is why he ruled the way he did.
A while back, the Sage explicitly said that whenever he answers a rules question he won't use his own judgement even if he plays it differently at his own table. He would always answer the letter of what was written in the book since he did not want 2 tables using 2 different rules whenever possible. He stated that any statement from him that contradicted what was written in the book would be constituted by a bunch of people on the internet as an official "errata" to the book and he didn't want to issue "errata" from on high like that. Any errata was going to be carefully considered and discussed among the whole team to decide whether it was NECESSARY. Thus, the very small sheet of errata that they issued.
So, we should expect the Sage to be extremely literal in his interpretation of the rules. Unfortunately, this makes his rules next to useless since even he has said that the rules were written to be interpreted by a human. We should expect most DMs to use their own judgement in terms or interpreting the rules in the most logical and straightforward method as possible to make the game fun for everyone. Our group had this discussion and decided that characters who throw daggers with precision sounded like fun and were within the genre of D&D and we all didn't like the idea that some weapons weren't ranged when used at range.
And what it comes down to is that there's no way to "break" the game by using thrown weapons with any ability in the game that requires the use of a "Ranged Weapon". Most of the time choosing to use a thrown weapon instead of a Ranged weapon is strictly worse. Sometimes its approximately equal.
If an idea isn't game breaking, seems logical, fits within the genre, and is fun to play with it meets all the criteria to allow, IMHO.