I read it close to 20 years ago now, but my recollection was that all of the characters being unlikable and everything they wanted and did (basically, worrying about status) being uncompelling was kind of the point.
Emerson tells you not to care about what other people think. Fitzgerald gives you an extended opportunity to experience not caring about what other people (particularly "high status" people) think.
It's not that the characters were unlikable. Unlikable characters can be great.
My hate for Gatsby was more about the paper thin plot, the shallow characters, and the purple prose. Why should I spend any time thinking about what these characters do or say when, as far as I can tell, they basically have no internal life. They are simple, one dimensional beings who just do things with about as much spirit as a typical video game NPC.
Most of the books I was assigned in high school I actually enjoyed or at least didn't hate.
Depends on why you read fiction. If you read it mostly for narrative, sure. If you read it mostly to explore ideas and to enjoy the artistry, probably not.
Emerson tells you not to care about what other people think. Fitzgerald gives you an extended opportunity to experience not caring about what other people (particularly "high status" people) think.