I think it's really, really awful for parents to not bother to get their child diagnosed. So, so sad.
It's also awful that people describe having ASD as 'a label'. This is the biggest bullshit ever. Naughty is a label. stupid is a label, ASD is a diagnosis.
It's also something that no one else has to know about if you don't want them to. Kids don't have to tell their friends. Parents don't have to tell their friends if they're embarrassed. The idea that with disability there's a 'stigma' is so outdated and disgusting to me though. Anyone who thinks there's a stigma to a disability is not someone I'm interested in knowing.
DS's diagnoses have helped him beyond compare. He doesn't feel odd now, he knows why he sees things differently. He is really happy having Aspergers as he links it to him being clever and being an excellent programmer. It explains why he likes a lot of time alone. He no longer seems himself as clumsy now he knows that he is dyspraxic. He now knows why he isn't great at PE. He now knows that he's not just careless and clumsy and that there's a reason he's a bit of a loner - those are labels that can no longer hurt him because of his diagnoses.
The diagnoses have also helped him hugely at school, there was no problem him using a laptop at school or being in a small room for exams or using ear plugs when needed.
However where getting a diagnosis has been really invaluable has been in getting a job. Interviews are known as a huge barrier to people with ASD getting a job. More and more companies are now recognising this and offering questions in advance to autistic candidates. I spent years and years worrying that DS would never get a job because no matter how clever he was, if he couldn't perform at interview then he didn't stand a chance. But thanks to getting the questions in advance he is know working as a software engineer and loving every minute.
I have never for one minute regretted getting DS diagnosed, I really, really wish I had known that I was ND as a child and understood why I was different and struggled with the things I struggled with. Unlike DS despite me being clever (research degree with distinctions) I have never had a job that matched my abilities. I'm so glad he is valued and understood.