I get where this is coming from, but put frankly, it just feels like another way of putting the blame on another group of people (this time neurodivergent people) for not fitting into a rigid mould.
Saying that traditional dress codes are "helpful" kind of ignores the fact that those rules were never made with everyone in mind - in fact they were usually made with a very specific set of demographics in mind. It ends up sounding like, “just follow the rules and you’ll be fine,” when actually the rules themselves are part of the problem.
Not everyone grows up learning these unspoken codes that were made by a very small minority of people and pretending they’re neutral just reinforces that divide.
It's not putting the blame on anyone, I am speaking from my own personal experience.
I have always (up to the present day) been pretty much indifferent to my appearance, and have also in the past been mostly close to people who are not particularly bothered. More recently I have close personal relationships with people who are much more focused on their own appearance and I have found this helpful, and would have benefited from it in the past, in that they will highlight things that I don't care about but they do (and therefore so do others).
In addition, being indifferent, I would simply not notice the difference between one style of male dress and another, because this was not something I was interested in or paying attention to. However, by reading about it and therefore informing myself of the specific differences, such as collar styles, tie knots, etc., it becomes a series of rules or separate items, rather than a more amorphous "clothes", and I also thereby became more appreciative of the visual impression that is conveyed, which again is helpful from my own perspective, in attempting to emulate that.
I don't see the class origins of dress codes as affecting whether they can be helpful to neurodiverse people by providing formal structure and rules. I know that there are law firms that claim to be disability confident, offer guaranteed interviews, etc., but these turn out to be "terms and conditions apply", such that they probably don't mean much at all. I would therefore, personally speaking, prefer to be aware of the rules and faux pas, rather than hope over experience that the world is understanding, particularly given how many people don't care about whether you are neurodiverse and will consciously/unconsciously discriminate against you.