Reddit does not own human communication. Do not give it such power

/s is a really useful tool to convey non seriousness in a textual conversation. Reddit did not invent it. The people that realized there was a gap in understanding and starting to textualize sarcastic tone did.

Just like emoticons and memes where embraced by internet culture before. The human condition earns to expressive itself in new and more nuanced ways.

In other terms: Language is open source.