People can be toxic but you really just have to say "???? It" sometimes. I remember when I first started tanking in WoW and didn't know pulls super well but went and learned. Even leveling my first class on ARR I went and watch video tutorials for all the dungeons and primal fights BEFORE I joined the duty finder.

If you are truly set on learning how to do something you will put in the time and effort to learn your class, the fight, and what you can do to min/max your character. If you know you're character has its ducks in a row then anyone booting you from a group or not bringing you to your first EX is missing out on a potential skilled player and will be hard pressed to find other players to fill that spot especially at this time.