I have two autistic children, who are not aggressive. In fact, their disability makes them more vulnerable to aggression and bullying from others.
I have seen more than once though, that they have been attacked, and when the parent of the attacking child is found, they say 'Its ok, they are autistic'
AIBU to think this is not an excuse? If a child is known to be aggressive, then it's all the more reason for parents to supervise and manage there behaviour carefully, rather than excusing it.
I have seen these parents unwilling to correct their child when they are aggressive, or even supervise or remove them from the play area so they don't attack again.
I completely understand how difficult it can be to raise a child with additional needs, but this lack of parental boundaries and supervision, together with facilitating bad behaviour seems completely unacceptable.
It's for this reason that I do not take my children to special needs groups anymore, as they deserve to be safe. They are gentle and don't even hit back. I have had to work on their assertiveness, that it's ok for them to say 'stop' and to move away and speak to an adult.