Did the title get your attention? Well, let me clear up something. I don't think that Baha'is raise brats intentionally or that a particular faith group has complete ownership on raising brats or that brats are an inevitable consequence and fixed in their lifelong development to become adult brats. In fact, naming a child a 'brat' is a label that alters one's view and therefore may limit the adult's ability to recognize a moment for positive reinforcement of good behavior.
Also, I do not think that I have the answers to raising everyone's children.
With that written, I am shocked by how many people, in general (in or out of the Baha'i community), conduct either laissez-faire or dictatorial styles of parenting. Both extremes result in a strange brew that leads to behaviors and understandings in a child that aren't quite useful for themselves or society.
A laissez-faire style leads to a child that does anything and everything, has little or no social graces, and finds disorder to be normal. A dictatorial style leads a child to have limited personal growth in as far as setting boundaries for themselves and the natural inclination for the fire of creativity (among other things) is doused.
A child needs love, trust, and respect (much like anyone else). However, a loving parent who allows the child to do nearly anything isn't providing a framework where the child will be safe. Once a child is of a certain age (2-3), communicating in a loving manner what is and is not expected of them begins to build respect and trust in the relationship. That communication comes from the parent, but it is also important for the parent to allow the child to share their emotions and thoughts, to a certain extent, such that they feel heard. "I understand that you like jumping up and down on the couch because it is fun, but you can slip and hurt yourself. Here are two other things you can do (A &B), which do you you want to do?" A few things that parents may do that can be helpful are:
1. Label the behavior, not the child.
I have witnessed communications from a parent and a child that would be considered rude and unruly if said to another adult. Demeaning the child's soul is not the role of a parent, rather the role is to provide boundaries that allow for personal growth. A child is not always 'shy', always 'rude', or always anything - unless the parent reinforces it by name calling (including being called a 'brat').
2. Tightly connect (in time) consequences to behavior/words
If a child does something that is disrespectful, then at which moment do you attend to it? As soon as humanly possible! Connect the action to discussion and the consequence, so that the message is clear. I have heard of some experts recommending that one must provide children with all of the options possible and let them choose. In this way, the child's inner being will develop as intended and without harm from parental influences. This is ridiculous when taken to an extreme. Parental influence can be a good thing!
3. Listen to and try to understand the child
Some parents don't try to understand the source of the child's emotion or thoughts. Granted, it is difficult at times to do this, but it will reap benefits. Listening and being respectful to the child is modeling the behavior you expect from him/her. How many adults are frustrated with each other due to simple misunderstanding? Now, make one of those adults into a child whose vocabulary is much less and you'll end up with screaming and tantrums (even some adults continue to do this because they didn't learn how to recognize their emotion and use it wisely).
4. Be Consistent
Nothing damages a good framework of trust, respect, and love more than inconsistency. It isn't easy to always be consistent, but try to be consistent about the most fundamental things. Certain behaviors are never to be tolerated and the consequence should be well known by both parent and child, and followed through.
Well, with those four to think about I add one more thing...
Choose your 'battles' wisely. You alone need to identify what is significant and what is not. Sometimes, just like adults, the child needs to share his/her feelings and not have a solution. They need to be heard and understood. Neither the laissez-faire or dictatorial parent will find balance, nor peace.