I am sorry this happened to you... this is normal in MMO's. No matter how nice a majority of the community is, you always have that small percentage that likes to be utterly rude/elitist and only think of themselves. I know I've dealt with that type, and I am sure everyone in this game has at least once.

Please don't let it get to you... if you haven't found a really nice LS/FC look for one that is active in doing events within the group. I have a wonderful group myself, and I've done 99.9% of my instances with my LS and try to help anyone in my group that needs a run or fight. I only had to do the duty finder once to find a healer. Best of luck to you, and I hope you run into as few of those people as possible from here out~! <3