There are some things easier for a computer to do, like lots of simple math, given that the computer can accurately store the result of each calculation, whereas people have difficulty doing so for 1000 integers.
And there are some things that are relatively easy for humans to do, like communicate with natural language. Sarcasm falls into the later category. This is because human understanding is heavily social and conceptual.
It’s like expecting AI to sum up 1000 integers without errors, when people can’t even do that 100% of the time.