So you agree food is subjective and everyone has different taste. But you can't see why one would say JJ is awful. That is truly baffling.
I get people's palates differing or preferences varying. What I don't quite understand is how that can be used as a qualifier for people who may be considering going to eat at a place without anything of substance to go on, no reasoning, just "it's the best" or "it's great."
I was recently told that Uncle O's has amazing roast beef Poboys, and they're the best in BR, so I give them a try, and they turned out to be garbage, resembling very little to me when I think of what a really good New Orleans Roast Beef poboy is supposed to taste like or the texture, ingredients, etc. just lots of food, and tons of mayo and mushy bread.
When people say things like that on this board, I think it's just respectful and reasonable to expect some kind of breakdown of the food in order to put it into perspective, and that's for the very reason you said, that people have different tastes or expectations, and perceptions of what they think is good, or acceptable, or legitimate, proper, etc. there are elements of the dish that either make it so, or not.