You can also find a link to this video in the comments section of that post.
In this video, we see how people react to a (staged) argument between a parent and child--first a mom and son and then a mom and daughter--about costume choices. In both cases, the child wants to wear a costume that is "gender inappropriate."
For me, watching this video was pretty frustrating at first, but there was a nice turnaround in the end. Though I still wish that at least one person had been on the boy's side.
Thanks to Mandy for sending me the link to the video.