Speaking as someone on the spectrum: Autism Speaks isn't necessarily bad for suggesting that autism is something that should be cured, but they are bad because they offer bad advice that ends up harming autistic people rather than helping them.

Suggesting that autism is something that should be cured isn't an inherently bad thing, at least to me. It's like suggesting that we should try and help paraplegics walk again, in that my life would be a lot better if I wasn't autistic.

they are bad for both reasons