Now, I will not make a long post, as many have already offered their input, but I think greater clarity should be offered to newer RPers as to standardised MassiveCraft only RP etiquette (S.M.O.R.E. - I only put the 'only' in there for the O). I recall remaining inside the lore's confines to a reasonable extent since I made a character application before I started RPing, but it took me a long time to learn RP etiquette because I found no resources guiding me to the proper systems. I became a noble and I still didn't know what powergaming was, that was after almost a month of RPing quite heavily. I found the environment frustrating because I was engaging in higher level RP, with little understanding of the lore. Therefore, I think people should be presented with a link to a concise page with information on RP etiquette and a brief overview of all the races. This can then link to the deeper information if they are interested. This way, anyone who is semi-interested can quickly and easily learn the ropes behind RP. From there, they can develop at their own rate and with the friendly help of MassiveCraft's community, they could become a highly valued member of the RP community.
In terms of people's attitudes towards these 'noobs,' I suggest more positivity. By treating them with harsh words, sighing, face palms and eye rolls you ruin their confidence in RP, ruin their perception of the community as a whole and ruin their MassiveCraft experience. There's no reason to roll your eyes when someone does their best to RP, even if they are playing a 'sk8r boi.' It might be tough, but just do your best to gently guide them to the right information so they can get into it. You might wish to discuss with them the concept of MassiveCraft RP and glean whether they truly are interested in it. If you think not, perhaps give them some pointers towards PvP, or simply explain to them what RP is all about. Just be nice and don't come on the forums and complain about 'noobs.'