Its a Halloween movie.

My interpretation is its a celebration of the holiday of Halloween and a response to overly concerned parents and the religious right of the 90s who were worried about satanic and dark imagery and the nefarious impact it could have on children. The movies usage of christmas imagery and the way Jack Skellington becomes infatuated with it is all about underscoring the point that while the trappings and traditions may be vastly different, ultimately the core spirit of Halloween is the same as the core spirit of Christmas.

Its about bringing joy to one and all.