I would still say the rule was fairly applied. We all have a responsibility not to induce others to sin (have sexual thoughts about her). If our behavior is doing so, we should modify the behavior if it is reaonable to do so. In her case, it was reasoanble as she could have chosen another dress.
Of course this concept carries no weight and has no application value in the secular world- but the dance was not a part of the secular world. This may make me seem fuddy duddy to many here, but perhaps my religous back ground enables me to see the men's point. As to whether they should have pursued that point after she had been "cleared to enter" is another matter.
I posted one out of a couple hundred different sources. Here are some others;
Homeschooled Slut Kicked Out Of Prom For Giving ‘Impure Thoughts’ To Creepy Dads
Va. teen kicked out of prom; photo shows dress met length requirement | FOX13Now.com - Fox affiliate.
Teen Girl Kicked Out Of Prom So Her Dress Wouldn't Lead Boys To 'Think Impure Thoughts' | ThinkProgress
Virginia teen: I was booted from prom because male chaperones checked me out* - NY Daily News
Teen Girl Ejected From Prom Because Horny Dads Can't Stop Staring
Girl Kicked Out of Prom Over Dress, ‘Provocative’ Dancing | FOX8.com - Fox affiliate
Girl Kicked Out Of Prom Because She Might Make Boys Think 'Impure Thoughts'
There are words for people like you.
And as I pointed out yesterday, the reasons for her being kicked out of the prom are all over the board.
Your OP said it was because the "dads experience 'impure thoughts'".
Think Progress said it's because the dads worried about the boys getting impure thoughts. Gawker said it's because of the dad themselves. Fox said it's because of her dancing. Another Fox said it's because of her dress.
The very fact that everyone is reporting a different reason based on nothing but her claim on her sister's blog shows it all right there.
The joke is on you.