These "gen-Z" rules are great if you are 15 and have nothing more to do with your time than worry if Emily fancies you or not by how many chins she gave her ascii text art smile. I was there: when I was a teenager on IRC and MSN messenger I was on hooks at the smallest detail; how long was it taking someone to reply, have they received the message, oh-no they're replying now I better not type out a message, they signed off "ilyvm" not "ily" they must have really liked me today...
This sounds quite dismissive, and it is in a way. "Old" people don't need to understand the difference between "k" and "k.". Gen-Z need to communicate to their audience and there's nothing more embarrassing than old people learning young people lingo.