Do you realize that many of these lead to the destruction of cultures, languages, traditions and maybe history too?
One of the best examples I can give you is native-americans (indian-americans). Yes, many of them were killed, but many of them mixed with other races. It is said that over 50% of white-americans have at least a native-american ancestor. And even those that still exist, many don't have a language of their own, they do not follow their traditions/culture, etc.
I know many people who are mixed but yet they choose to learn or to try only one culture (one of the parent's cultures) while ignoring the second one completly.
I also know many people who are mixed but consider themselves to be of one race only especially those who are half white half black.
I'm not against these sort of relationship but I think they are too hyped right now... eventually they might lead to the destruction of the society as we know it, for the better or the worse, but I know one thing for sure... many people died in order to protect a country, its culture, its language, its tradition and while doing so they have made history. I think all of these should not be in vain... Im just saying.