I certainly think that mixing different cultures can bring out the best in people. If both parents are stable mentally, they will instill the best values from each of their respective cultures.

The problem is, race mixing often comes with hidden agendas such as getting a visa out of the country from where the poorer side is from, treating the spouse like a trophy if one side assumes his/her culture is superior, and passing on values which are not great but are assumed to be by a less than intelligent parent.

In the USA for example, it is easy to live in a bubble of your own culture for years. The 1st generation of immigrants usually choose to live life like this. The 2nd generation generally start emigrating out of their 1st gen communities and start assimilating. But the USA is a bit weird or exceptional depending on who you ask about this.