How shocking!

That's understandable, humans do in many cases too

As much as I love sarcasm that is done well, I do find that it translates very poorly to written text unless explicitly noted with /s or something like that. Even when annotated, it's extremely rare that a sarcastic comment actually furthers discussion or makes a meaningful point. If a person is using sarcasm, odds are pretty high that they aren't engaging substantively anyway. Given the difficulties with detection (which even many humans fail at) it seems like trying to detect sarcasm would just make the tool a lot less useful and would be mostly antithetical to the project goals anyway.