Is applying bindi against Christianity?

A friend of ours who is a christian surprised me other day when she did not want her daughter to wear a Bindi for a group dance while the other girls( incidentally all hindus) would do it. I wonder why she could object even for a 5 min. dance with a bindi. I did not ask her this as it might be a sensitive matter to her. Well, although being a Hindu, I feel it is my personal choice to wear a bindi whenever I like to. Honestly I do not use one daily. Only for indian occions I use it. I would be intersted to know if there is a reason behind the objection in Christianity.