You know, I kind of don't want to defend this show. It's just "OK", not really anything special. And I CANNOT see the supposed huge budget, it looks like "TV" rather than EPIC and movie-like.
But I don't get why people hate it. To me, it's not any worse than "Tales of the JEDI/Empire", and I certainly think it's better than "Visions"
So, I kind of have a related theory.
We know that the Jedi did SOMETHING that they don't want people to know about, but I also think it's highly unlikely that Disney will let Jedi do anything outright evil, so here's what I think is happening:
As with the old Watergate cliche, it's not the
crime, it's the
coverup.
In a world where the Jedi have the ability to literally manipulate minds, you can't really trust memories or flashbacks. SO...I think Osha's childhood memories don't accurately reflect what really happened that day. Specifically, I suspect this:
Osha, after getting restrained by her people and sister, freaked out and somehow did something that directly or indirectly led to the death of her coven and the supposed death of her sister. Some kind of Force temper tantrum. Somehow the Sith remotely sensed this psychic tantrum (e.g. like Yoda sensing Anakin killing the Tusken Raiders) and marked OSHA (not Mae) for recruitment to the Dark Side.
The 4 Jedi who were there (with what they thought were good intentions) broke their own Order's rules and collectively Mind Tricked Osha into thinking what we saw in the 3rd episode was what really happened. This is the crime that they're hiding from Osha, their Jedi superiors, and the rest of the world. Serious abuse of the Light Side's ability to control minds, in order to implant false memories. (I think there's some kind of weird "Priest abuse" analogy they're going for).
After that they felt guilty about it and tried to mold her into a padawan, but it didn't 'take' and she eventually went off on her own.
The Sith got a hold of Mae and tricked her into thinking she's a potential Acolyte. But in reality, she's just bait to capture the real potential Acolyte, Osha who already (unintentionally) the kind of emotional violence that they're looking for.