The text hits spot-on the main issues: people don't play a role in RPGs anymore, they metaplay by treating the RPG as a board game, not as a fictional scenario. Roleplayers take into account the setting, time, what his character knows at that point, that his character can't see the name written above that person, that his character can't go using words like leveling and such, and among other things. Metaplayers just go around calling people by their names, using memes and slangs from his current era, telling everyone their level, they don't play the role at all.
However, there are many profiles of players and all should be acceptable. What isn't acceptable is having metagamers calling themselves roleplayers just because they play (not) a RPG.
A good text overall and I'd post a comment, if it allowed anonymity.