But what about people who are in different parts of the world and don't inherently understand your meaning? That is terrible behaviour to downvote the notation.

Text is notorious for not conveying context. Sarcasm can easily be seen as serious by some people, why is why we have the /s notation to make it obvious.

People aren't idiots, they come from different backgrounds, locations, languages, and all use English as a common tongue. Have some consideration and stop thinking you are so big and clever.