As a new player, the end game community is so unwelcoming.

I started playing this game less than a month ago, and right now my main is an ilvl 889 DH. Now that I am at the point where running raids on at least normal difficulty is necessary, I find it so difficult to join groups where players aren't complete elitists and unwelcoming.Today I just tried running Emerald Nightmare on normal for a the balance of power quest line, and there was only one group. The raid leader made it evident he wasn't allowing any "LFR raiders" and would boot from ONE mistake. Since it was my first time I was nervous, but I needed to run it and I wasn't confident in running my own group. We get up to Cenarius and I did everything fine up to that point, and then one player accidentally pulls a mob before the Cenarius fight and got instakicked. I ignore, knowing the leaders mentality. Then the kid he kicked says "Oh come on man" and the leader replies with an insult that includes "you should have been swallowed", and I just thought that was completely unnecessary so I say so. The leader then argues with me who did nothing wrong and boots me. How can a new player like myself really enjoy or even learn end game when there's a large amount of players who act like this?TL;DR Raid leaders are completely irrational and unwelcoming when it comes to new players or even just players who make small mistakes, making it hard to enjoy end game content.EDIT- If this post came off as strictly complaining, that was not my intention as it was more of a post asking for advice to better my in-game experience. I appreciate those who replied with the intention of giving advice and helping. Those who only have negative things to say where it isn't really deserved are not appreciated.