Hmm...what a strange comment from your chiro.
My vestibular therapist from my very established health care company told me that icing my neck regularly was very beneficial. It helped slow down the signals from the amygdala after brain injuries like nausea and dizziness and panic attacks.
I agree with other posters here that I am not sure where I would have been that first year after my injury without my ice packs-I still use mine very fondly.
The icing also reduces swelling and inflammation and is generally and accepted practice for Olympic athletes as well RICE (Rest. Ice. Compression. Elevation).
So-I'm not sure quite where or what the science behind your Chiro's opinion is, but I might get another one.