I would simply say "Nobody cares how 'good' you are at this game." At all. Period. Seriously. No one cares. Not even a little. Your accomplishments, knowledge, experiences, gear, titles, crafts, gil, etc are all meaningless. Yours are and so are mine. No, I'm not being sarcastic.
I agree with the OP, not you.
I do care how good others are at this game because their skill level when playing with me directly impacts my experience, which means more fun to me.
I do care if there is a cadre of good players out there that can help test, and figure things out. This makes everyone's playing experience a little bit better.
I do care if the lowest common denominators that think wearing any equipment, using any abilities, and coming as any job to any event, regardless of proven vs. unproven strategies, gets to make their opinion heard because SE has unfortunately shown that they listen to this group of players. In fact, that is pretty much 99.9% of the official forums and look what that got us.
I do care.
I also think people shouldn't be giant bags of you know, things, like the OP said, but I think this whether or not they are good. The two are separate in my opinion. I've met at least as many of both good and not good players who are like that.
-Don't be a giant bag
-Be a good player
In the grand scheme of life, no one cares if you play this game or not, much less if you're any good at it. That's my point. No one should ever be a d-bag period, and part of avoiding being a d-bag is keeping things in perspective. Knowing the ins and outs of a game world doesn't make anyone special or superior to anyone else. It doesn't make one inferior either. Having shiny loot isn't a reason for me to respect someone. Not having shiny loot isn't a reason for me to think less of someone. Don't define someone based on their skill in a game, and don't let that be what defines you either. Define them on how they behave, and behave in a way that you'd be proud to be defined by.
I agree with you that no one should be a d-bag.
However, everything else you said is irrelevant to the OP.
I do and will continue to define others by their skill while I am playing this game
because their skill and attitude are the only things that matter in the game. You bringing up the straw man of respect for a real person by the amount of in game skill/gear they have, has no relevance to any topic about FFXI. This is not what is being discussed. We are discussing attitudes vs. gear in the game. We are not discussing whether gear in game merits respect of a real person.
If their skill is lacking, I will not do events with them that matter to me. I will help them for charity reasons, and I do and will go out of my way to explain the mechanisms of the game to give them the proper tools to succeed on their own, but I will still think that they should have read forums and help guides and ask questions to others besides me, just like I did. And I will not invite them to events whose real life time depends on their skill and gear until they get that up to a minimally acceptable level in my opinion.
If their attitude sucks, I will not interact with them again. Period.
You see, I am the one who gets to define who I will group with. You are the one who gets to define who you group with.
My bar just happens to be slightly higher than yours.