Dustin Hoffman is horrible

He was playing a character with a very rare, very specific type of autism - savant syndrome, which causes a person to have incredible skills in certain areas, along with extremely low skills in other areas. Hence, basically mental retardation, except in those areas of extreme expertise. Everything that I've read about the syndrome and everything I've read about Hoffman's portrayal of the character, says that he was extremely authentic and credible in the role. Even within that syndrome, I would imagine that there are varying degrees of impairment/abilities. He, obviously, was extremely impaired.

My wife worked with clients who represented all variations of the spectrum for 38 years. She said Hoffman's interpretation was nothing short of brilliant.

I suspect you're trolling.