I really reccomend reading Unbroken, it wont take you long as its a short story, not a book. It is also free, right there on the short story page.
Yeah, it was from a combination of many regular draenei having shunned the Broken for being “forsaken by the Light” (in spite of Velen’s efforts to prevent that sort of attitude, it’s hard for even him to unilaterally override those sorts of fears) and an early rejection of what they considered "ways of the enemy’ due to the orcs having once been shamans.
Ultimately it took Velen continuing to preach tolerance along with the Broken shamans showing their worth and the benefits of shamanism to win over a lot of the other draenei.
Since then it seems like the draenei have mostly come around to the idea of having shamanism around and stopped roundly shunning the Broken, though as with any people there are probably individual outliers who remain uncomfortable with it.
Though having other Alliance races’ shamans around (dwarves in particular, since Kul Tirans are a pretty recent addition) may have further acclimated them to the idea that shamanism isn’t inherently a problem due to its historical Horde associations.
I just didnt know if it was in unbroken or maybe somewhere else in a TBC quest line way back a decade ago… jeez man…
It didn’t help that originally all of the Draenei shamen were Broken. And some of those Broken in the Swamp of Sorrows were insane.