I do not think that FFXIV has a reputation for "fake positivity." It sounds like maybe you have joined FCs that aren't the right fit for you. After the initial welcoming phase where people get to know each other it may turn out that you just aren't really a good match. That's on you, not the FC. Leave and try out a new one. An FC isn't required to "be open to new things, ideas, and people" if it doesn't mesh well with their already established vibe.