I understand all that, but you still completely missed what I said...
You focused on me telling you to improve, what I actually said was to find a group that suits your skill level and through that, you will improve. In order to do that you need to stop being so negative and actually be positive about improving in your role. I know that other people experience this, but its not actually the action that is important, but rather how you move forward from it. There are very experienced raid groups that will have no mercy for underperformance, there are also midcore raiders who would give you the time of day, however they will not do so if you have a bad attitude towards improvement. You are expected to research fights, you are expected to discuss improvements in rotation and to synergise with your healing partner, and that can't be done if you are at odds with other players.
I really want to help you get a good group and to help you play healer better, but you need to be willing and not so confrontational about what is expected of you.
(btw, what im saying is theoretical in terms of the game as a whole, in actuality - finding a group for alex with only 2 months until stormblood may be harder than it was, but groups should be recruiting for 4.0)