Idk, I feel like if someone you see as a close friend, who you told everything about your pain and anxieties, who already handle you in a way that makes you feel worse rather than happier after a heart to heart conversation, just say something very hurtful without consideration then answer with less than 2 sentences while confronted before just stop talking to you for a couple of months while still commenting under your vent posts in an ungracious way, it seems perfectly normal to just detach yourself from that person and not let them pull you in again by acting like they care.
It's easy to pretend to understand someone by keeping involving yourself in their life and listen to their traumas but it only makes it worse when you end up knowingly use that knowledge against a person who is already in a bad mental state.
One error can happen, but if it's just a matter of the person not putting on gloves because that's "who they are", then they can be who they are with someone who will not suffer from this.