One thing I've learned in my long years playing MMOs is that it's really hard to get along with some people - and if you really don't get along with someone, especially if there's a good reason for it, such as selfishness, then it's just going to keep getting worse. Games are downtime, fun time, relaxation, free time, and that's something that makes it even harder to deal with. After all, you should be enjoying your free time, not "working", or doing things that feel like work - and dragging someone through content, putting up with someone you don't really like, etc. all count as "work". And before someone else tries to say it - sure, breaking none of these "unwritten rules" is against ToS, etc. However, there's still such a thing as courtesy and respect, and this showed none of that.

So, no. I don't blame you in the slightest for feeling frustrated and angry about this. It's pretty clear that if this had been a first-time offense, it wouldn't have been such a deal-breaker, but it's everything leading up to it, too. As to whether or not leaving is the right option, I leave that up to you - ultimately, yes. You should get away from this person and not do anything else with/for them. I don't know what your situation is and whether or not anybody else would go with you, or if people would be willing to group with you if you stuck around in the FC & ignored the leader, etc.

I had something similar happen about a year and some change ago. I won't go into details, because it's water under the bridge, but I had a pretty bad falling-out with our former FC-leader, and there was this sort of "lead up", as well. How the whole drama was approached, however, turned off most of the others in the FC as well, and every single current-geared 70 left along with me when I quit the FC. The FC leader realised that they'd shot themselves in the foot, gave the FC over to someone we were still friends with, and left. We all went back, and now we're all pretty happy. I'm lucky - I still would have left, but without the rest of the group going with me, things wouldn't have turned out anywhere near as well... so I get just how hard a decision this is.

Ultimately, I hope you have friends that understand/agree with this and support you, but either way... well, you have my sympathy. There are childish, selfish people all over, and it sucks any time you spend your time on them only to be repaid with trouble. I hope you sort it out, and that you can find another group of folks if your current group isn't willing to back you up.