This is exactly what someone meant when they said you're taking their criticism (that you asked for) to mean that they think your kid is bad. No one said anything even remotely close to that.
In your first post, you said that it was very negative, implied that teachers are lazy or uncaring because they only want "easy" students, he only gets messages from most that he isn't good enough, and that they're giving your son the shaft. None of that even includes any of your follow up posts. If those comments don't mean that you think the teachers are unprofessional and uncaring then I'm not sure what else they could mean.
You were not given the wrong impression. If Teacher A says a child is acting out, why wouldn't you ask teachers B, C, and D to determine if it's a problem with your child or specifically Teacher A? Just because you chose not to do that doesn't make it their fault. Whether it was an oversight or denial on your part is up to you to decide, but it's irrelevant now. You know now. You're taking the steps to work on it. Let the rest of it go. What they are doing has not helped, but neither has what you've done. Seems like at this point the teachers are getting ALL the blame, you're excusing yourself because you "didn't know" and Ben gets excused because "it's funny".
I do find it rather strange that you will post, word for word, his progress reports and your letters with the teachers but will not answer the questions regarding the Scouts meeting or his "it's funny" comment. I do have to agree with the poster that wondered what you are going to do if the neuro results come back negative (which I hope they do). If there is no medical reason for his behavior, then what? Who takes the blame then? And if you don't get those neuro results tomorrow you better start raising hell over it. REGARDLESS, you deserve your money back. I'd call the insurance company and fight the payment. A delay like that is ABSOLUTELY, 100% unacceptable.
Obviously, I don't know what you said to her to warrant this response, but I'm going to go out on a limb and say that it was probably out of line. Suggesting that a teacher focus on the positive and to try to give him more positive feedback is insulting. The problem is not that she doesn't focus on the positive. The problem is your child's behavior. Full stop. If the teacher never gave Ben any positive comments ever, she'd be an ineffective teacher but it wouldn't excuse his behavior. What you are suggesting is that unless your child is being told how great he's doing, he is allowed to act however he wants. To give advice on how she should be doing her job and using his home behavior as a rebuttal to her original letter (that you asked for) is just...I don't know.
You have two children. Multiply that by 100, add in some legitimate special needs students, some poorly behaved ones, some downright rude ones, parents that hover, parents that don't care, parents in denial...then imagine someone chiming in with a "You're doing it wrong." on a daily basis. And some lunatics actually WANT to do the aforementioned for a living. That is the exact opposite of uncaring. I, honestly, don't know how they do it. Good teachers are worth their weight in gold. GREAT teachers are priceless.
Search Youtube for Taylor Mali What Teachers Make. They truly have one of the most thankless jobs out there.
This is a very good post! Except of course where you call us teachers lunatics!

Although some days, in all seriousness, it feels like that...
I do feel that that OP has totally misunderstood the tone and purpose of the teachers' comments, as I mentioned before.
They are not negative whatsover, but as a parent who has a child who is exhibiting problematic behaviours, she feels this way, and nothing that multiple pages of responses from any of us is going to erase.
I am not sure what follow up email she sent, but to imply that the teacher was not positive is a concern for me. I can show you teachers who are not concerned, and they don't send emails, nevermind detailed oriented emails with many positive words in them, such as the ones that the OP posted for us.
We seem to have a perception problem here, and there isn't much that will fix that for the OP, except at the school level. I think because her child doesn't exhibit these issues at home, she may feel that school is the problem, but that is not how it works.
Diagnoses have now changed to where you don't need to present in multiple environments anymore to be diagnosed with ADHD, etc. If her child is struggling at school, then that is what is focused on, period.
I feel badly for the OP's son's teachers at this point, as those comments were very helpful, and showed how caring they are for her son. They were positive in nature - mentioning that you aren't going to give special seating so as to now isolate a child is very positive, and proves that they get it. I am confused as to how OP feels they were given the wrong impression as parents? Our job as teachers, since we spend more time during the day with your children than you do, is to tell and show you exactly what behaviours we see - and his teachers did just that, with detailed responses that are very helpful, if OP lets them be...
I do wish OP and her son the best of luck in figuring out what is triggering his school issues. Whether it's medical or academic, both or neither, there is work to be done, and at this point, it can't all be done by the school. Whether he is diagnosed with dyslexia, ADHD, etc., is important, but not necessarily for the teachers, as it sounds like they are already implementing accommodations (behaviour chart is good), regardless of an official diagnosis, and those are signs of good teachers.
Home, school, parent and child is the ideal partnership, and it seems like OP is trying to get there, but in my professional opinion, she is putting up obstacles on her end, and these will surely hurt her son in the end.
Tiger