Yes, but also no.
More users would be great for the fediverse, in theory. Right now Lemmy (and Mastodon) can attribute a lot of their users to people unhappy with Reddit Inc. (or X) in some way. Throwing more unhappy people into the user base would probably not lead to good outcomes.
Personally I think Lemmy and Mastodon will never get the critical mass of users needed to maintain healthy communities because the only thing they have to offer is a less bad clone of an existing network.
X is bad because a malignant political demagogue is actively destroying what most people liked about Twitter. Reddit is bad because reddit inc. cares more about profit more than the needs of the user base. But the platforms they created and/or operate aren't designed with a federated model in mind.
If the fediverse is ever going to move out of the technically savvy, early adopter nerds phase I think it's only going to do that through something new and better than what already exists.
The short answer is because autism is different from sexuality and the same system that works for one will not work for the other.
I would actually caution against embracing any label as part of your identity because as you have observed the autism experience is universally different. So too is the gay or lesbian or transgender experience. These are words we use to describe aspects of ourselves, but too often come to define us instead and enable exclusionary behavior such as gatekeeping identity or depening isolation for anyone who doesn't fit neatly into a label.