I think a lot of parents, teachers and well-intentioned grand parents are very judgemental. I run into this all the time. Parents give me these disapproving looks and make sly comments. It's all I can do to keep track of my boys. They are super energetic, dramatic and little goofs all the time.
My boys are different in their reactions to discipline, direction and their confidence levels. I can't do what other people suggest. I have read multiple books, go on parenting blogs, talk to family counselors, etc. Everyone has different advice. I try to keep things consistent and use my best judgement of how to run my household. What may work for someone else and their children is not going to work the same way for you. Take it with a grain of salt.
I would tell her you have read them, tried different methods, and your children do not respond to those techniques. Tell her your children are more active, and there's nothing a discipline technique can do to change their personalities, cognitive associations or energy.
We have to raise children as individuals because every person is not a clone of the next. We can't teach, direct or encourage every person the same. We each have different motivations, understanding and ways of processing information. You can't go through life teaching a method. You have to teach the child. When we try to treat each child exactly the same, we end up not being fair to either of them. We have to find out what is the best for each child and encourage them according to their own needs and desires.
When I put my 5 year old in timeout, you would think it was the end of the world. His little ego completely falls. It takes days for his ego to pick up. He is completely burdened and hurt. His emotions completely melt his self-esteem and outlook. He needs direction and reprimands given in a very subtle and gentle way. Sometimes he is being more defiant, and I have to be rather stern. That's about all it takes.
My 4 year old is the complete opposite. He must have ADHD because he has difficulty listening, holding still, following through on tasks, etc. He has a kind and compassionate heart, but he has so much energy that he tends to be overly aggressive... even when trying to show love and compassion. He will hug too tight, throw the ball too hard, play wrestle just a little too rough. He's a tough little guy. He needs stern direction and continual reminders that poor behavior and bad choices result in timeout. He can't sit still in timeout, and I generally have to hold him in my lap and make him sit still. It's not that he is trying to be defiant. I think it's that he just doesn't have the ability to use patience and wait.
I think as parents we have to identify if he is using every possibly form of restraint and attempts at good decisions to be good. I have been battling with whether to put my son on meds for ADHD. I finally decided that others will always see him as being defiant because of his high energy levels. I don't want him labeled and treated as a bad kid, so I am having him tested for ADHD and possibly other learning disabilities. With time and effort, he can learn how to control his behaviors, burn off his energy in positive ways and react appropriately. Eventually, he will be able to stop medications once he learns how to better approach learning, patience, etc.
Perhaps your child has ADHD. It might be something to look into before school starts and he's too far into the school system. Once children are labeled, I feel like there is a lot of prejudice against us. People will not admit their personal judgements and prejudices, but you--as a parent--can see that our children are not treated the same. Perhaps your friend is trying to give you helpful advice to help you see this. If the different parenting methods do not work, you need to look into something else so your child can be successful at school and other activities. There is an expectation to react a certain way when we go to social functions. If your child cannot try to change his ways, he may be reprimanded for things you do not feel are a big deal. However, the school system can be very harsh with detention, in-school suspension and out of school suspension for trivial things like speaking out of turn, not following directions, not listening, not being quiet, etc. I am sure your child is a very good and well-intentioned person, but others may not view him as that. It's unfortunate that society makes everyone fit into this little box of acceptance. Our children have to put on the good front to assure they have every opportunity for success.