I think most of you are influenced by our 30 odd years in Div 1/ Premier league.
Some of us are old enough to remember CCFC as a Div 3 and even Div 4 club.
Jimmy Hill drove the club upwards with a lot of razzamatazz which not everyone enjoyed.
In the top leagues, not every season, but enough to create a perception, others in football saw us as a small club overachieving, and treated us as a bit of a joke. Eventually the inevitable happened - we couldn't afford to stay up and sank down the League.
I don't think it's so much that people hate us, just see us as a bit of a joke. Nothing that has happened in the last ten years or so will change that view.