The young people are correct in their assesment.
It would be a strong man indeed who could look at this women dancing anywhere and keep his thoughts in order. But, to have it happen in Church is Blasphemous.
Another thing, the gown is made to be sheer from the top of her legs down. It is plain in the video that men would be able to see her legs.
Saints like John Vianney or Louis De Montfort taught strongly against any forms of dance.
To think that this is "not as bad as it seems", is to think like Pope Pius IX said. Those that hold the Catholic Doctrine yet with one drop of poison are to be avoided.
Alex, Alex the Lion and, Spouse of Jesus, stay strong, you seem to be developing a good sense of what it truly means to be Catholic. Never be disuaded by those who suffer low grade fever due to modernism.