It isn't. Who told you so?

Not at all it stimulates them in a bad way and can cause hyperactivity

It lets them taste their own bile.

Why would anyone, ever say such a thing regarding any child? But to use an autisic child in your question is just "WRONG"!!!!!!!!!

Autistic children often spin as a form of self-stimulation. It probably isn't a good idea to allow them to do this b/c it often gets them over excited.

Some children's sensory systems, crave the spinning motion. For some children it may be used for calming and reorganising there sensory system. But yet for others it might over excite them. Every child is different, what's beneficial for one may not be for another. It's very important to talk to a qualified Occupational therapist, they will know best how to answear this.

My son has Asperger's syndrome and since he was age 3 he has loved swinging on swings and twisting the swing to spin in a circle. He also loves jumping on a trampoline (with netting for safety) in our yard. He seems to use these activities for self-soothing. If he becomes hyper or agitated in the course of the day, we say, "Do you want to jump on the tramp?" and his answer is always yes. His mood is typically gleeful on the tramp and if his younger brother joins him he will talk to him and engage in pretend play with him like being superheroes. They fight mock battles against each other and he often does 180 or 360 spins and more recently forward somersaults. Aftr a half hour of this he is noticeably calmer and the positive effect can last for several hours. Why the tie on the trampoline helps is open to debate. The spinning involved in these exercises may help him to mature his vestibular system (involved in balance and locating one's body in space) and a more general explanation may apply as well. Many studies have shown that exercise in general improves mood for everybody (not just people on the autistic spectrum). A theory of Asperger's that I accept is that these individuals are highly anxious, the main reason being that they are unsure how to interact socially even though they desire to be social and accepted by others. Therefire, any activity that helps a child with Asperger's relax and maybe forget their difficulties for a while is a good thing. My advice is simply keep trying things with your child and if something seems to help them keep letting them do it. I don't see any potential harms from swinging or bouncing on a trampoline. Mike M.