This is a massive topic and for many different reasons...
1) for born-in's the WTS encourages (almost polices) children to be a target for bullying at school. No xmas, b'days, religious instruction and having. Doing door to door, no bad language, having to turn the other cheek, not joining in the fun stuff (discos) and not being able to date etc etc.
2) each KH is filled with personalities - some controlling types that bully. But all JW's are encouraged to put on the new personality which I believe is about displaying victim-like (sheep-like) qualities and therefore are open to bullying for any number of reasons.
The general rule though is if someone treats you badly and they're more spiritual (eg elder) then you are wrong and must pray. It's easy to get a bad reputation just for standing up for yourself and JW's are counselled to hold their tongue and forgive when treated badly. That just allows the bully to get away with it and do it again.
If you want to leave the organisation then bullying is often actively used and always involved as a threat (implied by the WTS).
3) in the preaching work some JW's use bullying tactics albeit generally more subtle. JW's believe they are 100% right and have God's backing so - they will preach to others - ignoring and rarely even listening to other people's opinions and if they disagree - well they're damned at Armageddon. Just turning up on someone's door - (normally it's 2 vs 1) and hammering through topics without the person being able to prepare can be quite intimidating.
I can honestly say I have never bullied in the cong - mostly due to my personality type - but seen it many times. I also was not bullied at school due to a combination of living a double life (avoided all references where possible to being a JW and what that meant) and having a set of cool friends who stood up for me.
I am angered though at how the WTS pushes it's young to "make a stand at school" and almost wants them to be bullied so this can be blamed on Satan and then they won't have any worldly friends. Also how some JW's act in the cong. If it were in the world they'd get a fist in the face and would learn, but in the cong they just keep getting away with it because the GB will back them up. GB policy on shunning, marking ones in the cong and how it encourages the spiritual class system (DO, CO, Bethel Elder, Elder, Bethel Mini, Pioneer, Mini, Active Brother, any Sister, Child, marked one (not sure where the wives of the DO, CO etc fit)) fosters an environment of bullying.
I have known of cases that led to some suffering depression and becoming suicidal.
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