No one has said that new players are the problem. The problem is rude players and players who could be doing a lot better but do not do so out of sheer laziness (not out of gear). Also, from my experience, a lot of the time it is the player given the advice that becomes rude, and not the other way around (not all people giving advice are polite, but the majority of the rude responders are the players being called out).
If someone's new to something, and I can help with their rotation and tell them how to survive in a fight, I will do so in a polite manner. Again, new players are not the problem. The most annoying players are the ones who are doing what I like to call "skill roulette", and when you tell them how their rotation works, they either ignore you completely, or become rude. I have never been in a situation in DF where someone has been called out for not optimizing their rotation, but they certainly have and SHOULD be addressed if they have absolutely no idea what they're doing.
This is a multiplayer game, and if you choose to purposely play in a way that hinders others, then YOU (not you directly, this is a general statement) are the problem. Doing your correct rotation is not being an elitist or a min/maxer, it's far from it. Doing your correct rotation is what you're SUPPOSED to be doing. As a DPS, you don't get to say "I'm gonna play however I please" in a way that harms the group, because if a healer or a tank does that, the group will fail, and you are no exception.
Also, "fun" is a rather subjective term. To a lot of players, fun is getting the most you can out of your class and running content as smooth as they can, while to others, it can be doing whatever they want. None of these players' idea of fun trumps the other, but purposely harming the progress of a run is selfish and inconsiderate no matter how you look at it.