We’ve reblogged posts about this topic in the past here and here. I think it’s important to make a distinction between cultural exchange in a multicultural society, cultural appropriation, and cultural imposition. As you note, there are a lot of great things about living in a multicultural society including the exchange of customs! There are a number of different opportunities for people to engage in each other’s customs.
Contrasting scenarios:
You are not Indian, but you are invited to an Indian wedding and your friend the bride helps you pick out a sari to wear to the event. (Cultural exchange)
You are not Indian, but you decide to wear a sari for Halloween because you think it’s exotic and interesting. (Cultural appropriation)
You tell your Indian friend she should have a “normal” wedding and wear a white gown even though she says she wants to wear a saree. (Cultural imposition)
Or:
A Jewish couple you are friends with held a wedding last month and you noticed that one of the components of the ceremony was the groom breaking a glass with his foot. You are not Jewish but you think that it looked pretty fun and you decide to incorporate it into your own wedding ceremony. You share this idea with the newlyweds and they are visibly upset with you but you don’t understand why. (Cultural appropriation)
The company IKEA of Sweden opens multiple stores across the world selling stylish furniture and delicious Swedish food. (Cultural exchange)
A Fortune 500 company requires all of it’s employees to wear European style business suits; while the company states that exceptions can be made for religious dress, employees are reluctant to request an exemption from this policy because they are afraid they will be given a hard time. (Cultural imposition)
A hipster fashion designer incorporates “Native-inspired” feather fashion headdresses in his line, modeled by white women (cultural appropriation.)
A Native American high school student is told to remove the single symbolic feather from her graduation motor board as it is against dress code. (Cultural imposition.)
An American man of Middle Eastern descent is called a “terrorist” while riding the bus for wearing a keffiyeh. (Cultural imposition.)
A South Asian woman is called a “dot head” because she is wearing a bindi and becomes fearful of wearing a bindi in public. (Cultural imposition)
A white American woman is complimented for her trendy fashion style for sporting a keffiyeh/bindi, etc. (Cultural appropriation)
It boils down to this, really: Engaging in practices encouraged by the dominant culture is not cultural appropriation…particularly when individuals experience discrimination for not assimilating into that dominant culture. Things like suits, European furniture, and even white weddings (which also has secular origins) have been heavily pushed by the dominant culture either through imposition or through open cultural exchange.