Stats don't matter and I'm assuming their respective usage and roles in the NBA vs college don't matter either for your argument. I say that because Edey went from being the #1 option in college and fed the ball all game long to a 4th/5th scoring option in the NBA.
You're making my argument for me.
That's because he wasn't good enough to be a #1 option. He played more than enough games to force himself into the frame of being a go-to option for the Grizzlies, but his play didn't warrant having those volume of touches. This is why despite him having that role in college, putting up those numbers, he wasn't good enough to replicate it (in relation) when he hit the league.
You brought up college numbers/stats in this thread. Ironically enough, I pointed out their NBA stats for the rookie seasons and still, that doesn't matter... for this argument. Now you're saying Castle had more impact in the NBA... how are you quantifying that? Because he put up better surface level numbers... right? Wait? What are we doing here?
I'm measuring it by how well he can create his own offense, how he adjusted to playing against NBA defenses and how he forced himself into having a bigger role (where he ended up averaging 19 ppg over the last two months).
Your mistake here is failing to see the representation of Castle going from 11 ppg at UConn to 15 ppg in his rookie season, whereas Edey went all the way from B2B 22 ppg seasons in college to 9 ppg in his rookie season. Your mistake here is failing to see the representation of 19/20 year olds having different trajectories than a 23-year-old who should be much further along than what he showed during his rookie season.
How is this not evident to you that putting up numbers in college shouldn't be a directive of when a player should be drafted?
But even that is hilarious because when you pull up their advanced numbers, Edey has a higher PER and a higher Win Share

Better defensive rating, better offensive rating as well
You just referenced a bunch of stats that are predicated on the lineups a player is in, and since the Spurs only won 34 games and the Grizzlies won 48, it would stand to reason the player on the better team would have better advanced stats based upon who the play alongside.