Some JWs do use shunning as pretext for cruelty, but there are plenty of exceptions.
When I was being shunned by my best friend there was an instance when we accidentally met face to face (not in the KH) in a narrow hallway. Since the only way we could get away from each other was by turning around and going in the opposite direction, it was a very heavy, awkward moment for both of us.
She stared at me. I stared at her... I saw that her eyes were beginning to tear up. I was going to say something when she suddenly turned her back on me and briskly walked away; probably so I wouldn't see her cry.
She definitely did not want to shun me, but she had to. She wasn't an independent adult who could go anywhere she wanted. She was a 15 year old girl whose dad was an elder. When her half-sister was DFed, both of her parents resolutely shunned her, so my friend could have no doubt over what would happen to her if she did not shun me.
I want to remind you that this person was my BEST friend. I had known her since she was seven and I was eight. We were like siblings. I can't just shrug my shoulders and dismiss her as a fair-weather-friend who was forced to show her true colors because of the GB's shunning policy.
And my story isn't unique. So many ex-jws have had same experience. Shunning destroys friendships and families every day. Good people get hurt on both sides. It needs to stop.