I really hope the little boy is alright. My son is almost three years old. It really doesn't bear thinking about.
I have a brother who is a couple of years older than me (he's almost 40) and he is profoundly autistic. He lives in a supported home with one other autistic adult and live-in carers. He is essentially "locked in" because he is non-verbal and has very limited ability to communicate.
He has a number of triggers, including dogs, children, coughing and people crossing their arms. We don't know why some of these triggers exist, although we have sometimes wondered whether certain behaviours may remind him of negative experiences in the past. When distressed, he can become aggressive and has attacked people before.
Because of this, he cannot simply be taken out into public places in the way most people can. He does go out, but only under carefully managed conditions. Walks are usually in remote locations where there are very few other people around, and if a potential trigger such as a dog appears in the distance, his carers will often change direction or return to the car. He also goes swimming once a week, with the local council making special arrangements to close the pool for a couple of hours during a quiet period so that he can use it safely. It is not easy, but my parents and his carers make it work.
If it does turn out that the person responsible was an autistic man with significant support needs, then the carers involved and those responsible for overseeing his care have serious questions to answer. They must be held accountable.
Taking an autistic adult to see wild animals was a bloody stupid thing to do. As a non-meat eater, I'm already pretty opposed to zoos. This has only reinforced my view that they're fundamentally horrible, horrible places.