Dezzistar- a traditional, long shanked hackamore can be very damaging, yes. I have found, however, that when someone says hackamore, what they really mean is 'bitless.' If you follow the link I posted in my previous post, you will find that what is being suggested has no leverage, and a padded noseband, and is overall a very gentle bridle.
ETA- A shanked hackamore should never be adjusted so that the noseband lies over the cartilage. Not only can it cut off air, it can, as you said, break the cartilage, provided you're abusing it.
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