Pointless abstraction would be breaking down games down to their very bones, then arranging them on the floor saying this pile of bones is that genre, and this pile of bones is that genre. You can separate every game into it's smallest elements all right, but whatever the guy in from of the monitor experiences will be lost in all that detail. Are GTA and Forza Horizon the same genre? Both are driving games, both are open world sandbox, both have missions, both have you gaining money, both have licensed soundtrack with popular bands. It's practically the same game, except it's actually not.
BG2 has you rearranging gear and talking to people, but no one with the right mind would argue that it's an adventure game, because those mechanics are not the core gameplay. Getting the living shit kicked out of you is the core gameplay. Meanwhile PS:T is a game of God how do I avoid this shitty combat, and that changes the entire paradigm. Both games are made of very similar elements mechanically, but that doesn't automatically mean those mechanics combined into the same thing.
This makes no sense to me.
No one -- including you and Agris -- ever played PS:T and came away thinking that managing the party's gear was a form of puzzle-solving, in part because the game was so easy and in part because the game had almost no barrier along the main quest where you'd need to up your stats to bypass barriers. In other words, the argument
only has merit if you think that this "break down to bones and compare" approach makes sense.
What you're really saying is, "PS:T felt like an adventure game to me, feelings can't really be articulated, but they are real." Sure. If, in fact, PS:T felt like adventure games to you, then you're 100% correct in describing your feelings. That said, overwhelmingly the people who say PS:T is an adventure game say that not because it actually felt anything like an adventure game to them but because they are aggressively patrolling the boundaries of their preferred genre (a particular subset of RPG) and are using "adventure game" as a pejorative shorthand. I am extraordinarily skeptical that anyone (including you and Agris) when finishing PS:T thought to himself, "Wow, this really reminded me of Monkey Island and King's Quest."
I
do think that PS:T is similar to Japanese RPGs. I think it's dumb to call it a jRPG, but it's less dumb to call it a jRPG than it is to call it an adventure game because some of PS:T's defining features (a well-defined player character, an eclectic cast of well-defined and long-winded companions, a huge word count, easy combat) and smaller features (e.g., flamboyant high-level spell effects) are closer to jRPGs than most Western RPGs and because Avellone admits that jRPGs were a heavy influence on PS:T. But jRPGs aren't at all like adventure games either -- they essentially
never feature inventory puzzles, very rarely have environmental puzzles (
e.g., Lufia II), and including large amounts of combat and grinding. The Codexian meme that jRPGs are "adventure games" rather than RPGs is just another example of this pejorative usage.
If you wanted an apt pejorative for PS:T, I would say that "visual novel" would be the one you're looking for. You'd be wrong, but that's the least wrong pejorative of the three (adventure game, jRPG, visual novel).
---EDIT---
Ultimately, if you're going to use labels, those labels have to rest on something other than idiosyncratic feelings or they aren't useful for communication. Common usage, key features, ancestry, and creators' intent all make PS:T an RPG. What is on the other side of the ledger?