However, just like basketball has different ranks, the gaming community also has ranks. You cannot expect the casual, once-a-week basketball player to play on the same level and skill bracket as a professional and paid player, do you? And just like the players themselves, different skill brackets have different skill requirements; a casual workplace basketball competition can't be held in the same vein as the NBA in regards to skills and technical knowledge goes. There a common expectations of what is required, yes, but in my books, I expect dungeons and any DF content to have any type of player to be put in a party with me, with the only requirement that we have the skill level and damage/heal output to complete the dungeon in an adequate time period REFLECTIVE of dungeon difficulty and player skill.
If the person in question is ACTIVELY holding back by performing beyond sub-par, that is something that needs to change. Someone however performing at an adequate level as their current skill bracket, and managed to complete the goal i.e. WIN, I see no reason to condemn their playstyle. Expecting everyone to perform close to the potential limit of their class in every content is like expecting fastfood restaurants to turn out three-hat quality products. It's not going to happen. You, as the skilled veteran player, can play to the best of your potential and outplay your fellow DF members, just as how a skilled basketball player joining a small competition will outplay both his team and their opponents. Just don't expect others to be in the same level as you are.
Blaming them isn't going to make this circle break anytime soon. Maybe we have a bad impression of the representatives because they have a bad impression of us? Ever heard of give and take? If I was the developer, I certainly wouldn't wish to re-visit a place where I'm treated with disrespect and scorn on a daily basis. They are only human, after all.