Look, not every fan is jealous of another club because it's bigger or has more trophies. Some people love their club and that's it.
A lot of the new glory hunter Chelsea fans are foreigners or the younger generation. They don't care about history or class.
It's the same with City fans. Miles and miles behind United in trophies won but I doubt most of them are jealous of their city rivals just because they supposedly don't have history or class.