This is something that is not allowed in Islam. There are many chaste women amongst the Christian communities across the world. One should not conflate the degradation in the West as being 'Christian'. Many acts of degradation in the West which Muslims see or read about are indeed perpetrated by secularists (not Christians) or by nominal Christians who identify to the religion very loosely. As somebody who was born and raised in the UK I can vouch for this.
Islam is the religion of mercy and justice
Of course it's unjust to label Christian women in such derogatory ways. We should try to give these women dawah - invite them to the Truth (pure Islamic monotheism). Immature insults on the net directed unjustly to these ladies will not produce any good at all. In fact with these immature insults one is insulting the families of many of our scholars - many of them (both past and present) converted from Christianity to Islam.
Here a few points from Sheikh Muhammed Salih Al-Munajjid of Islamqa which will help us deal with non-Muslims:
Islam is the religion of mercy and justice.
Muslims are commanded to call non-Muslims to Islam with wisdom and beautiful preaching and by debating in a manner that is better. Allaah says (interpretation of the meaning):
“And argue not with the people of the Scripture (Jews and Christians), unless it be in (a way) that is better (with good words and in good manner, inviting them to Islamic Monotheism with His Verses), except with such of them as do wrong”
The Muslims believe that it is not permissible, under any circumstances whatsoever, for a Muslim to mistreat a non-Muslim who is not hostile towards Islam; so the Muslim should not commit aggression against him, or frighten him, or terrorize him, or steal his wealth, or embezzle him, or deprive him of his rights, or deny him his trust, or deny him his wages, or withhold from him the price of his goods when buying from him or withhold the profits of a partnership if he is in a business partnership with him.
The Muslims believe that it is permissible for a Muslim to treat kindly those non-Muslims who are not hostile, whether by offering financial help, feeding the hungry, giving them loans if needed or interceding with regard to permissible matters, or speaking kindly to them or returning their greetings, and so on. Allaah says (interpretation of the meaning):
“Allaah does not forbid you to deal justly and kindly with those who fought not against you on account of religion nor drove you out of your homes. Verily, Allaah loves those who deal with equity”
Quotes taken from:
Invitation to Islam
Jesus taught people to do the Will of God (Mark 3:35) in order to become his brothers, mothers or sisters. A Muslim means one who submits to the Will of God. Do you want to become a brother of Jesus? If yes, become a Muslim. Now is the time.
Learn about Islam: