You can say that the neurodivergent people you know "live no differently than anyone else " but that must be based in personal experience ,as part of being autistic is masking and there are lots of different experiences in the autistic community , I'm not going to use functioning lables as those terms are outdated and inaccurate ,and only measure how you contribute to society . Instead i will say things like low support needs/high support needs as that categorises people by how much support they may need. A lot of the autistic voices we hear are those that have low-medium support needs ,which is probably who you would discibe as not seeming any different or only having 'quirks' but those people are only a fraction of the community there are many people with high support needs that may not be able to share their experiences and might not be listened to as it might not be as digestible to others. But even though people have low support needs that doesn't mean they dont struggle and it definitely doesn't mean their autism isn't a disability. As autism is a disability ; and its not a bad thing. It is a neurological and developmental disability which can affect how people communicate and interact with the world, Etc. It is something you are born with ,it affects everyone differently like all people can experience similar things but it affect them differently. The only way to understand autism is by having personal experience, listening to Autistic people, do research if we're not sure of something/ want to open a discussion. All the things I've said pertain to my own experience as an autistic individual (which is why i haven't mentioned ADHD or ADD as i dont have personal experience) Or from reading articles and listing to other neurodivergent people. That is my opinion and how i view the subject .