> I have serious doubts that an autistic advocate with low support needs, as opposed to 'neurotypicals' or impacted parents, are meaningfully more qualified to represent the needs of autistics with high support needs

You think a parent without any autism is more qualified to speak than someone who has autism but a different cluster of symptoms? Because being a parent makes you an expert on what exactly?

The is a video of the spokesperson of autism speaks. Her autistic child is in the room and can hear everything. She talks about how bad it is for her to have an autistic child. How she wanted to kill herself by driving down a cliff. Again, while her autistic child is in the room. She is acting like her child is not even a person.

Autism Speaks is a hate group of abusive parents.

Those advocates with low support needs are the ones that are actually making an attempt to give those high support needs a voice. Not by speaking for them but by taking down barriers so that they can advocate for themselves. Because guess what? High Support needs autistic people are still people.

Just because someone is non-verbal does not mean they can not communicate in other forms. They can advocate for themselves if given the tools.

Support needs are multi dimensional, one person might have sensory issues, another no sensory issues at all but more social issues. Who has more support needs? They are different. And they can change. You can learn better coping skills, you can need more or less support as you age.