exclusionism is prejudice
There is this attitude among some people that culture is something that belongs to a person by birthright. This is a form of prejudice, and I hate it every bit as much as the rest. Anything that is exclusionist on the basis of the way a person was made (race, sex, family) is prejudiced.
Yet some people think that if others (whites especially) try to learn about other cultures, and possibly adopt their belief systems, they are 'usurping' their culture. This is bullshit. I do understand the drive behind it, especially for those who have been an oppressed minority -- there's the idea, "You did _______ to us, now you want to share our treasure? Fuck off!" I might have that attitude myself if I was an oppressed minority, because it is completely justified. That doesn't make it right.
If a person respects you, your race, and your culture, and they want to learn and perhaps even adopt your culture, you should be flattered! Can they pay a greater compliment to your culture than wanting to emulate it? As human beings, we need to recognize that culture is what we have made and are making it. It's constantly in flux, because it is shaped by very changeable humans. We should encourage the desire to learn about each other, to respect each others' beliefs and ways of living, and possibly to adopt those that resonate with our inner selves.
This was brought on because I wandered into a culture-focused community, hoping to find people celebrating their culture -- instead I found nothing but negativity and hate for others, and a very exclusionist attitude regarding culture and religion. I agree that it's justified -- but what good does it do? What good does it ever do to hate other human beings?