I know that a lot of people on the Autism spectrum have difficulty understanding, sarcasm, irony, nuance, innuendo, and reading between the lines. This is well documented, and does have some truth. This is not universal however. I use sarcasm all the time (though not in a mean-spirited way). I don't have a problem with irony and as far as the last three things I've gotten a lot better with them. I don't even see sarcasm as inherently evil it's just a tool that can be used for good or bad. It sharpens what we say which is fine but if we are telling someone off or using sarcasm to belittle or humiliate, it's going to magnify the impact. For me it can be handy with getting a point across far more clearly than direct language.
Where I do have a problem is with slow processing. I think slow cognitive processing in general is a common issue on the spectrum and not well documented enough. I believe this can cause many with ASD to be unfairly labeled as naive or gullible. Sometimes that slower processing can be a matter of a few seconds difference, but that could be enough to cause major misunderstandings. I can usually get other people's sarcasm but lets say someone is telling me off in the form of a sarcastic compliment. My first instinct whether I agree or not with the compliment is to politely say "Oh Thanks" and then realize a few seconds later that is was sarcasm. Then I'd be in double trouble since not only was I thrown a "fiery dart", but now I look gullible to ass to the embarrassment. This can provide a tool to bullies, esp. early in life. A classic example would be schoolgirls sarcastically hitting on a nerdy guy. He may fall for it or he may pick up quickly that they are making fun of him. Either way if he doesn't catch on fast or caught on just a few seconds too late he will be set up for humiliation.
Another issue with slow processing is that although it can affect the worlds most brilliant minds, it is one of the biggest signs to people that a person lacks intelligence, wit, or cleverness. After all one of the first euphemisms to describe mild mental retardation in polite is "Oh he/she seems a little "slow"- God love 'em".
I want to make clear also that there are many potential causes for slow cognitive processing besides Autism. I do think however that it's an issue that needs more awareness and attention.
I also want to point out that while I'm sure sarcasm is pretty universal it may not come off the same way to someone not native to the speakers language. Also, different cultures may not understand it the same way as others do.