I have no idea why people have such an aversion to it, but the only way I got my daughters past that phase after the first incident...and my mom with my brother, and my aunt with her son was to bite them back.
Not enough to break the skin, but enough to get a wide=eyed response. Then keep telling them that it hurts and you don't bite. My oldest didn't do it again after the first time. My second did it twice and the second time I bit her and gave her a spanking (because she bit the little girl I watch and left very nasty red marks on her pudgey little fingers). That was the end of that.
Every now and then I can see my second child acting like she wants to bite, but she won't. Even I have a strong urge to bite sometimes and I always have. If I put my sons pacifier (the soothie kind in my mouth) I have an incredible urge to bite down hard. My mom stopped me by biting me. It ended there.
Your daughter won't be traumitized. She won't have nightmares or anything like that, but she will learn that it hurts and she will think before she does it again if she knows there will be serious consequences if she does it again.
I didn't think my mother hated me because she bit me. My brothers didn't either. As a matter of fact, we love our mother dearly to this day. My cousin bit my brother on his back so hard it drew blood. My aunt had tried everything him and was very embarrassed because he did that. My mom told her to bite him back. She did and he never bit anyone ever again. A problem she had for months (actually was going to get him kicked out of daycare) she ended in 30 seconds.
So I'm sure there will be a total uproar because I suggested it, but it works and it doesn't hurt your child permanently in any way. Not sure why the old ways of raising out children became so bad. Especially since children raised the old way were so much better all the way around. They worked harder, they behaved better, they loved harder, they were just better kids all around.
So take it or leave it. Hope you are able to solve the problem quickly. Good luck!!