Why is your gentle, peaceful trans child on this protest in the first place then?
Because that protest is not calling for gentleness and peace.
It is calling for women to be forced to change in front of males, it is calling for women to be forced to see men naked, it is calling for women at support groups to be forced to recount their experience of male sexual violence in front of men, it is calling for women to have to share bedrooms with males in women only accommodation, it is calling for women to have to share prisons with males, it is calling for women and girls to be told they are allowed no boundaries, it is calling for them to ignore their instincts when they feel unsafe or that they are being violated. It is calling for women to be placed at harm to benefit men.
That is not gentle or peaceful. You don’t get a free pass on supporting all that because you help out at a community garden.
There is literally nothing in that judgement to make your child feel scared. If they are scared it’s because they have been listening to the lies of one side. And not listening to the other side. And it was a choice of theirs to do that.
My Ex H was autistic. So I understand well that your child’s iteration of autism MAY mean that the only perspective and experience that exists to them is their own. They may have rigid and inflexible thinking that makes it extremely challenging for them to alter their views or opinions. But you see, those of us who have lived with people with these iterations of autism get really tired of being told how we have to squash and suppress ourselves to support the autistic spouse. We get tired of damaging ourselves to be their human support animals. We know that our partners may lack intention to treat us abusively, but it still feels the same as being abused by someone who has intention.
So sorry, your child is engaging in activism to prevent women being kept safe from real harm. That is not a gentle and peaceful act. Your child does not have to hold a violent placard. By being on that action they are saying women being placed at risk and harm is how society should be.