I can't really say much about other games but I believe the reason it is so difficult for FFXIV is probably the way content is organized. This is just my opinion but I feel like the instanced raids and primal fights we currently have require a certain amount of precision that is really difficult to find among randomly assembled pickup groups. When people do experiment with pickups they tend to blame others for shortcomings when they experience losses which lead to further antagonism. From experience, a very friendly social linkshell of mine was pretty much torn apart after the Ifrit fight was introduced.

The above coupled with a strange "better than you" syndrome really diversifies the community and creates certain niches (linkshells) that pits people against one another as they endlessly one-up each other or exclude others because they're not a part of their group. It's highschool all over again! People who I was very friendly with 3 months ago might now completely ignore my existence while I attempt to say hi to them.

tl;dr- I agree with besieged-like activities but ultimately I believe people just have to be more friendly and remember that this is a game.