At the end of the day, you are playing the wrong game.
Four people only looking out for themselves isn't a team or a group, it is four people trying to get themselves through something without giving or taking. People with line of thinking is the reason why the game is as miserable as people are saying. All of the problems you are facing are things that can be alleviated by getting over yourself. You only sense of unity in your type of party is that you have 4 people that want to make it to the finish line. You are about as united as four people sitting on a bus.
I don't like people. I hate MMOs and having to depend on other people to do their job. However, just like real life, you can only do so much on your own. The purpose of an MMO in the first place is to force cooperation. I don't like it, but I play the game knowing that. Why should I willfully make things harder on myself? Give and take. As much as I may not like who I'm dealing with, I want to get to the content. A pointer or whatever is going to get me to my goal quicker. If someone takes it offensive and becomes more problematic, that person is going to be kicked. That person is going to leave. It may take you a moment to get a replacement, but if someone is going to quit over being given advice, which absolutely happens, they're going to keep running into a road block and either shape up or move on. Either way directly benefits me. My motivation may not be "pure hearted," but it gets me to my goal, it makes for less bad players, and it helps everyone. More importantly, I don't believe everyone's interests are being accounted equally if you're purposely allowing them to hurt themselves because you don't want to speak up. My gaming experienced is being DIRECTLY AFFECTED by someone not doing their intended role correctly. My interests are NOT being accounted for equally. If I am a DPS and that tank is causing problems for me, not because I'm actively or obliviously causing problems for him is one thing, but if he's doing his job completely incorrectly, he's not just causing problems for me, but the other people in the group as well.
I work a technical support job; if people could read the instructions, we wouldn't need these jobs in the first place. Depending on the nature of the job, technical support jobs mean that 90% of the time, the customer probably could have fixed something themselves if they spend a modicum of time trying to actually find the answer.
And here's a great idea; people can be rude because they think your words are making them look weak. "If I can get this far, why should I have to change it now?" Because people like YOU are letting them run into issues and do things incorrectly. People that I throw a helpful hint to don't "expect," to get help, but they appreciate it.
Most importantly, how are spamming Flash and uncombo'd Halone NOT detrimental? I am a Dragoon. I deal extremely high numbers. If you are not comboing correctly, that means I deal aggro. I can't be concerned with micromanaging to account for someone else doing their job incorrectly. If I want them to do something right, I tell them, in so many words. If they can't accept it, they can be ejected. In endgame content, it means I am probably going to die in short order. Not managing your aggro abilities as a tank is also going to mean that the healer is going to draw aggro. In endgame scenarios, you ARE GOING TO DIE. These scenarios ACTUALLY HAPPEN. Before endgame, you can simply brute force your way through it, not say anything and simply deal with it, but it does not work after that. All of these things happen can be prevented, but are allowed to happen because of people like you during the fundamental stages of learning the game.
You have absolutely no right to complain when you allow this stuff to happen in the first place. Your views of weakness and being self-sufficient do not work in these types of games. I share the same views in most cases, but if I want to play this game, I have to accept what comes with it. You should probably stick to single-player games.