Huh? No, not at all. Not unless you belong to a hardcore raiding FC, which wouldn't be the case in the example of someone more casual.
I am somewhere between casual and hardcore. I generally play about 30 hours a week. I have never been kicked for being new or not "being an expert". I've even talked someone through a fight I had never even done myself since I researched the fight beforehand. Best thing to do when you're doing content for the first time is simply say "first time" in chat when you start. 9 times out of 10 people will be more than happy to tell you about any mechanics you might need to know.
This game is actually one of the few MMOs that DOESN'T have a problem with being left behind.