Disclaimer: I have no quarrel with the mods using the term in the creation of this community. I understand why they chose it, as even if they share my disagreement with the term when applied to ADHD, there's not really a better inclusive term. "Mental illness" is really the only other option, and naming a community that would probably invite darker discussions that the mods might not be prepared to handle.
Another disclaimer: I think the term is perfectly valid when applied to autism, as autism is not, to the best of my knowledge, a mental illness so much as a difference in processing. Being autistic is only "bad" in the sense that our society discourages autistic traits. (Apologies if this is wrong; I'm neither autistic nor especially knowledgeable about autism.)
The term "neurodivergent" implies that there's nothing wrong with you if you have ADHD--you're just special and different. But my ADHD is an illness that requires treatment. A lot of people will tell you that the only reason ADHDers struggle is because society is set up wrong, but I don't think that's true, at least for me. Being unable to remember anything, unable to self-start, and hypersensitive to rejection would be massive problems in any world. Sure, the world today is particularly brutal for ADHDers in a way we could probably mitigate if we reorganized society to be kinder, but that doesn't mean ADHD isn't ultimately a disorder that some people need to treat with medication and therapy.
I mean no disrespect, but does the fact that you have to take medication to achieve your personal goals not suggest that something is wrong, or at least that you would still need those meds in a socialist utopia? I don't think there's anything wrong with taking meds, but I wish I didn't have to take meds in order to achieve my goals.
Lactose intolerance is actually perhaps a good analogy. Because, yes, life thankfully does not revolve around eating cheese, and you would certainly be much worse off if it did... but that doesn't change the fact that eating cheese without your medication will make you sick. It's still a problem you have to take meds for, even in a world where it's relatively easy to avoid cheese.
That's basically how I feel my ADHD would be without capitalism. Less bad, sure, but still a net negative that requires treatment and makes my life harder.
For more on why I consider my ADHD an illness, see my replies to Gaywallet later down the thread. It's literally tried to kill me.