As someone who has "successfully" masked for the majority of their adult life, all the while suffering in silence, I can say that this is a problematic take at best.

I am considered a "fully functional" adult from all outward appearances, even to friends and family. I'm lucky enough to be capable (with great internal effort) of typical "normal" things like participating in meaningless smalltalk, holding down a job, and doing all of life's chores just like "everyone else." However, unlike everyone else, I had to practice and endlessly rehearse things in my head to achieve the outcomes I desired. A charitable interpretation of your words would mean that "it's a problem", but who is it a problem for? The folks around me? Certainly not. This is invisible to others. It's akin to running monte carlo simulations of all permutations of outcomes before acting on decisions that others would consider trivial. For years I thought that was what everyone was doing. I eventually learned that "no one" did this, and I trained away all "problematic" characteristics of myself just to keep up the act.

So in lieu of your implications that 'passing' autistics "have no business getting diagnosed", I'd rather propose this instead: seek a diagnosis if your condition is debilitating in any way shape or form and would benefit from treatment, _regardless_ of whether or not your condition is externally visible or even apparent to others. A "fix" should be sought if you are suffering. There is no cure for autism, but there are many programs and medications that can help.

PS That said, it may be unwise to disclose your diagnosis to say your employer, unless you need specific accomodations for your set of symptoms at work. I speak from experience.

I didn't mean to imply masking doesn't come with a disadvantage, and I sympathize with the efforts needed in places where others have no stress.

Still IMHO the bar to treat it as a medical condition is higher than that. To take another example, one can be hyper reactive to dust, and that has surprisingly wide impacts on everyday life. House maintenance becomes critical of course and interior furniture will reflect that (e.g. a long fur carpet and other hard to clean convoluted forms are out of question). It also bars the person from whole categories of shops ans places, old libraries is often a no go, some shops/restaurants using encent or heavier room flagrance will also trigger a reaction. There will be whole categories of jobs that are also not an option.

This kind of predicament will make everyday life a lot tougher and require significant effort, yet IME will not be categorized as a medical condition until something critical happens. Like an asthma crisis that ends at ER for instance.

It is not "fair" in the sense that successfuly dealing with the health/mental issue is kinda taken for granted, but I also understand why we draw a line between conditions the person can deal with alone, and other conditions that require external intervention.

I could "deal with it", until I couldn't. When a seemingly fully functional person with no warning signs suddenly breaks down (often catastrophically), providers scramble and tend to misdiagnose since they're missing key criteria. Without a formal diagnosis, it can look like severe depression or psychosis or a number of other similar conditions that have very different treatment plans. Autistic burnout treatment is something entirely different, although it can present the same. A prior diagnosis would at least point them in the correct direction for treatment.