The full stop thing has been around since IRC networks, or I imagine any quick-response short message platform. No one ever explicitly explains it or notes it, you just pick up on it.
Same with the difference colours of laughter "lol, rofl, haha, hahaha, lmao, ha." They're all just laughing but I bet you had different ideas about how each of them feel. This happens with language at large, synonymous words pick up nuanced differences so that we can express ourselves better, they aren't codified they just spread naturally.
I think for full stops, it's like the difference between familiar language and polite language. If you are too polite with a close friend you give off the impression that you're not close enough for casual language, which can be insulting.
Same with the difference colours of laughter "lol, rofl, haha, hahaha, lmao, ha." They're all just laughing but I bet you had different ideas about how each of them feel. This happens with language at large, synonymous words pick up nuanced differences so that we can express ourselves better, they aren't codified they just spread naturally.
I think for full stops, it's like the difference between familiar language and polite language. If you are too polite with a close friend you give off the impression that you're not close enough for casual language, which can be insulting.