Koltira was risen during that particular attack, so it’s entirely likely that he wasn’t the only one.
I’ve posted about this before here but it’s worth briefly repeating that at this point in time, they were still high elves, not blood elves, so once the character broke free (at either point in time, because both are possible) they would have completely missed that entire post-Sunwell crisis and all the politics that stemmed from it. They might have began with very different points of view toward their Horde allies than others, and might have trouble relating to their kin because they’ve had very different experiences.