The "list" tends to vary a lot. Everything in moderation... some birds have allergies to foods just like we do, some foods are ok if cooked, some not. Some even list apples (because of the seeds). I've noticed a lot of lists out there that include a food saying that it is dangerous in general instead of adding in the stipulations regarding the preparation/feeding of it.
As for the kale, Scooty hates it lol. He will dig out every grain of rice and each tiny lentil before he even puts his beak on it and then when he does he either wipes it on his perch or slings it across the room lol. Even in the mash he managed to work around it. He can be a brat lol...just like me growing up I suppose