Someone was mean to me on the Internet

As some of you know, I spend a great deal of time on the Internet. I am bold enough to say to my professors that I spend so much time on the Internet that I am qualified to write papers about it. A lot of the time that I spend online is used playing games. These days, I generally like first-person shooters, like Counter-Strike or Team Fortress 2, where I feel like I am a comfortably average player. I've occasionally dallied in MMOs, having played Guild Wars devotedly for a little while. Right now, I play on Dungeons & Dragons Online, which is, notably, free.
All of these games center on the multiplayer experience, in the sense that without other people, there is no game. Even in MMOs, where it is possible to play through content by yourself, there are numerous points where it is simply not possible to win if you're alone. So interacting with other people is a big part of the games. When people are friendly and competent, this can make for an awesome game. When they are stupid or rude, well, you get the idea.
Something happened to me today that never happened to me before. Now, I have been yelled at plenty of times while gaming online for a large variety of reasons, but this was new to me. I was lectured, extensively and aggressively, on how to play my character, as I was, apparently, doing a terrible job.
On DDO, I play an elven ranger named Shenoute. The ranger's job is, historically, to shoot things with arrows and pet animals, all the way from the original Dungeons & Dragons days. In tabletop, where a Dungeon Master is interacting with you and crafting a story on a personal level, rangers can have all kinds of uses. Their ability to commune with nature, be invisible, and shoot people is rarely questioned. But when D&D hits the MMO platform, the tactics change. Thinking creatively is not important here; you must always be the biggest, baddest killing machine (or healer) possible or otherwise YOU ARE DOING IT WRONG.
The way I play Shenoute, I pretty much live on my bow. I shoot arrows at monsters. I try to manage how monsters hit my party, because I see them before everyone else does, and I also try to draw fire away from other people. I am going for a particular prestige class that is basically a sniper. Why? Because I think that would be awesome. And I like playing this way. I think it's fun.
But this is not enough for some people. It was not enough for the guy who decided to call me out tonight. We were breezing through quests on the hardest level with the greatest of ease, and halfway through a long quest, he turned around and started tearing into me. Why do you use a bow when everyone knows they suck, he asked. Ranged is crap, you need to switch to melee. Stop shooting at things and melee. If you don't want to melee, then why are you here? Why are you taking up space being useless? Oh, 'you want to have fun', whatever.
For this person, it was not enough that we were doing well and enjoying ourselves individually. He seemed to have every sundry detail worked out to exacting specifications for how it should be done, and any deviation is useless and offensive. He had to turn around and start accusing me of messing everything up for everyone. Naturally, I am perturbed by these kinds of people, for whom playing a game is a mechanical process with rigidly defined rules, for whom it is a matter of clockwork and machine-like efficiency. It doesn't matter if they actually succeed in this or not, so long as they think this way. Seeing someone like me, whose character has been haphazardly designed for maximum coolness and funtime rather than to beat the game at its own rules, is apparently unbearable.
I wonder if they are really having fun, or if yelling at other people and telling them how to play the game 'right' is their way of compensating for the fact that they aren't really having fun. Seeing what they are lacking, perhaps, they lash out. If that's true, it's pretty sad. I can't hope to understand why people like this go to such lengths to enumerate things that they may as well be performing statistical analysis to find the best class combinations. I really just want to have fun, so I left the party in the middle of the quest and found another one that picked up where I left off. I plan to keep running and gunning, even if it isn't the best class in the game, because that's not what's important to me.