The song talks about the issues of interracial marriage. I got reminded of it by this Ranker list of black-white marriages. Values-wise, it should not really be odd. But of course, the attitudes about these kinds of marriages are more influenced by culture and practices. For example, marriages affect transfer of property. If a marriage has a foreign partner or one from any different group, property will go that group. That is what many likely don't want. Obviously, the cultural ramifications of an interracial marriage affects towards it the most.
The song has a really catchy line, "Dream On." It's a very nice tune to listen to, but it also carries with it a message, one that hits attitudes around the world.