I agree, I think kids and adults like Abbie are often underestimated in their ability to understand things. She does appear to understand basic instructions, she can misinterpret certain things as most autistics do, but on the whole, she's a good listener. I definitely think she's not being given the correct help to fulfill her potential. I think she needs encouraged with the abilities that she has, that way she will either maintain or increase her abilities. Abbie does have a voice, just not a verbal one and often when she's' trying to communicate she's being ignored and misinterpreted. A&P need to do a lot of work to understand nuances involved and look at everything to do with autism outside of the basic things; sensory etc.
That person commenting has no idea about the autistic community. Most of us have no problem with people knowing we are autistic. Generally speaking, the autistic community (at least online) embrace our identities. It's not a disease, but it is intrinsically a part of who we are whilst acknowledging the difficulties we can encounter.
EDIT: Just noticed that person that commented is same age as Abbie (14) so I can forgive them for their comment.
EDIT2: Though that person is right! They do exploit her. I just disagree with the first part of their comment slightly just for the autistic community as a whole, but most of us aren't exploited online by our parents. It's funny they've been told they are disgusting by a kid.