I mean whatever the relative merits (or lack thereof of) concrit (or less constructive crit) leaving a disparaging comment on a 15-year-old seems kind of pointless. Like it's not like the writer is looking for ways to improve it at that point.
I agree with you that the people who want a different story should go write that story or at least look for that story somewhere else instead of complaining to you about having written a different story.