https://www.psychologytoday.com/us/blog/and-running/202012/behind-the-scenes-sarcasm
The truth is, chronically-sarcastic people frequently rely on this obfuscation to express emotions and communicate. These folks also often harbor passive-aggressive characteristics and simply don’t have the ability to be real about emotions, or fear confrontation were they to speak their mind. They therefore employ sarcasm, a sort of cloak-and-dagger approach to communication. It allows them to expel brewing contempt in a manner that feels safe. It is also serves as a repellant along with the smug demeanor many sarcastic people adopt. Oftentimes sarcastic, passive-aggressive souls don’t want people getting close due to an inability to handle emotional intimacy. Most people can only handle so much of them, even if they are truly a good person, because of their sarcasm. Said person gets their cake and eats it too.