Well this oval racing etiquette isn't proper to how you would do it in real life at all...
People tell you to pass on the left because that is the only way your 'pack' or group can start to get a faster overall time so they can either catch up to the front, or stay in front so nobody can catch you guys.
Basically if you are behind someone, you work as a team with slipstreaming back and forth... but at timed intervals when approaching corners preferably. In order to work together as this 'faster group', the leading cars ALWAYS should veer to the right when the car behind is gaining on him fast from the slipstream. Letting that person pass on the bottom/inside/left, he will gain sufficient ground and be well enough ahead of YOU to then to the process over again. If you can catch his slipstream in time (quite easy), gain on him fast and then gesture to move on the inside and he should let you through if he knows how-to do it properly.
That's all it really is, because all the oval racing really depends on is if you work with an opponent and do constant slipstreaming back and forth, and it really isn't for position... it is mostly done so people doing the same thing don't catch up to you or gain a position. If you try and block the inside all the time, you'll definitely get a bunch of spongebob noobs yelling at you for it. Best just to stay away from ovals and learn good racing etiquette on road courses instead :up: