1. Milder forms of autism are subjective enough and share traits with other mental health problems that it can be difficult to say with certainty what they are. I have personally not been diagnosed with it but at least one medical professional suggested the possibility after diagnosis, also I have very little trust in the competency of medical professionals in my country for any semi complex issues so I've avoided even trying to get a diagnosis as I feel it would be irrelevant.
In certain aspects of life I was able to function with relative normalcy, in many others not at all. On my personal assessment after many years of self assessment and reflection I do firmly believe I was born with at least a mild and/or adjacent disorder to autism. Could it then be said that I'd be faking the condition if claimed to have it, with all those caveats? if I am, at the very least I can say I'm not doing so knowingly. Considering myself to be at least autism adjacent is not exactly a source of pride, nor of shame for that matter, just an attempt to understand the strangeness of my self and life.
2. Beyond that, I'm tangentially aware of a trend in the disgusting amalgamation of monetized mental illness, otherwise called social media, where some people actively try to fake various mental or associated conditions for attention. I vaguely remember the case of someone that claimed to suffer from severe Tourette's syndrome, which I believe was the basis of their whole media presence, that was discovered to be a farce.
3. The age of the Internet 2.0 has had a bit of a swing effect on the issue of openness about mental illness, what was once utterly taboo, now its almost celebrated, at least amongst certain circles. For the shallow or immature claiming to have a whole collection of clinical mental illness can even be seen as a source of pride or attention and so, desperate for attention as they are, they do so.
4. There's probably a less malicious version of this effect, where a lot of children and teenagers going though relatively normal issues are constantly bombarded through social media and even their friends with all this talk about mental health issues and they may wrongly end up assuming that their relatively "normal" problems are actually a clinical condition.