This has been discussed by the community a number of times. The consensus in the community has always been that capitalised forms look unnatural in a vast majority of in-game messages. After all, none of the in-game texts are actual formal paper correspondence - they render spoken dialogue, e-mail messages, social media posts, and game messages. That's the rationale - if you are old enough you might remember that in the early naughties we actually did have capitalised pronouns in one of the first versions, and players were rather vehement in their objections - and we do not sea a reason to turn traditionalist all of a sudden. By the way, even prescriptivists from the PWN (for our non-Polish readers: the main Polish dictionary maker, whose experts run a language lab-style site, with prominent Polish linguists answering usage questions from the public) - who are conservative as hell in many of their responses - in recent years have started accepting the fact that capitalised forms are traditional, if not traditionalist, whereas the actual usage is more of a personal preference, and the younger generation no longer applies that particular prescriptive rule. From a practical perspective, keeping the formal/informal ergo capitalised-non-capitalised distinction throughout the translation database would be a nightmare for us and for the developers, so as long as we are consistent in our choice, it works fine.