Also, people have no problem minimizing the things as well, where pain again is a good example. In many situations, if it cannot be seen, secondary parties easily disregard it.
So, in conclusion, this confusion with the autism levels should not be a problem.
But what if low functioning and high functioning peers share many symptoms, but at different intensities? Won't that make the 'high functioning' peers more capable of understanding and thus speaking for their low functioning peers? In fact, there is a specific term for this - 'the double empathy problem'. Perhaps you should try a less 'ablist' approach to autism.
First of all, the reason this registry isn't going through is because autistic people who are functioning enough to speak out did so in solidarity with the entire autistic community. So far from polluting anything we are advocating for ourselves and our peers.
Secondly, this "high functioning low functioning" dichotomy is wrong so your framing it as a "us vs them" situation is off. It's a spectrum not a binary.
Third, presumably if they can't speak for themselves, and "high functioning" autistic people are discouraged, then the only people speaking for them are allistic people speaking about what's best for autistic people. When that happens, you get bone-headed characterizations like autistic people "never pay taxes, they'll never hold a job, they'll never play baseball, they'll never write a poem, they'll never go out on a date. Many of them will never use a toilet unassisted." and suggestions of registries, wellness farms, and soon enough genetic cleansings.
Finally, it's autistic acceptance and awareness month, and the autistic community has been under attack for a week. You're spending your Sunday calling autistic people "selfish" and characterizing their input as "pollution". Have some compassion please.
So, the only people allowed to talk about autism are people like you - those who do not have it.