Tell your local coffeeshop barista while they make your coffee. If someone starts to argue with you, just ask them very loudly, and repeatedly, why they support sex slavery. Then take your coffee and walk away. The entire coffeeshop will have heard you, and they will begin to fear being publicly shamed for supporting Islam and sex slavery.
Shame works, especially public shame. You will help turn the tide against sex slavery and Islam, one moment at a time.