If you go back a ways in history, you will find that it used to be that officers were comprised of nobility and other "upper class" types. Could you imagine an early victorian Duke or Lord sitting back and sipping sherry with a teenaged, illiterate peasant? Furthermore, part of differentiating the messes is to not only allow the groups of either rank to b*tch about each other behind closed doors, but also to add a bit of space to the Officer-NCO-NCM relationships. As an officer or NCO, if you're really close buddies with your troops, it makes it harder to (possibly) order them to their death. Having some divide allows it to be a little easier to that job.
Oh, and unless you are actually a Regimental Sergenat Major, in which case you would know the answer to this question, you will be asked to change your username, as it is misrepresentative of your rank or position.
