I guess they want to maintain their credibility by including listings for
events with proven attractiveness for people in their target demographic. If
you feel that they missed the mark, I suggest you resubmit the listing request
accompanied by a) a histogram showing ages of attenders (invite people to put a
tick-mark in an age band on a sheet when they arrive), b) photographs that show
people of the target age range.
If people in the target demo are not at your dance in any noticable numbers,
then you have a chicken/egg problem that the newspaper is not interested in
helping you solve.