Sarcasm is ubiquitous online. There is something about relative anonymity that brings out the cutting wit in…well, some people. There are those who don’t seem to understand the concept. They take sarcastic comments literally, or take offense because they don’t understand it’s a joke.
Until some genius designs a font that is used and understood by all as denoting comments as sarcastic, rather than genuine, there will be misinterpretation by those who are missing the sarcasm gene.
Communication is tricky.