we are progressing...probably a lot faster than most on this orb.
Anytime we make a claim about making progress we need to understand what scale we're using. Progressing towards what? The implicit scale here seems to be towards tolerance or towards realizing individual liberty.
What is not on that scale is marital stability. The most recent few 10 year cohorts of married people who have been studied show that interracial couples have a 50% greater divorce rate than same-race married couples. That too is progress if we are on the scale of trying to achieve high divorce rates.
Consenting adults should be able to marry other consenting adults without explanation to anyone.
Indeed. As individual liberty increases, community cohesion must decrease. There cannot exist community standards if every standard is only subject to individual preference. This conflict is one about balance. If you say that the expression of individual liberty in marriage need never be explained to anyone, then this damages community cohesion.
Secondly you imposed a condition that you prefer onto strangers, that of consenting adult. That's you, an outsider, imposing a condition which limits individual liberty. This is no different than other strangers imposing an in-marriage rule on people. For instance we could devise the following scenario, to remain a Jew every Jew must marry within the religion. If a Jew marries outside of the religion, then they are cast out of the community. This is no different than a ban on interracial marriages.
Do you really think there is some instictual preference for your own race?
Of course there is. We can derive this from a number of methods. Let me go through one method.
We start by looking at families. Is there a difference between how a father treats his own child compared to how he treats a step-child? Is that parental bond something that can be taught or be imposed by willful action or is there something inborn going on? The violence and murder rate against step children is astronomically higher than it is against biological children. So even with blended families which have every incentive to become one family, we see that wishing doesn't always translate into dreams coming true.
Step away from your immediate family. If we compare willingness to provide aid between a scenario where a cousin is in need to a total stranger, we see the cousin winning out. Extend the family relationship even further and while the effect diminishes we still see a greater bond than that felt towards a total stranger. Extend the family relationship even further and most people no longer even recognize a bond of kinship but they do recognize a cultural bond, the shared values, the common history and now compare an individual American in need to a starving child in Africa. The American in need takes a higher priority.
These scenarios DO NOT have have play out with 100% accuracy and they will still shape how people will live their lives, make their choices and choose their mates.
The world is a much smaller place and getting smaller every day, on this forum alone we have members all over the world. More people get to know others, the more we realzie ew are more alike than different.
It's the effect sizes of similarity and difference that are the engine driving diversity of groupings. Here's an example. Everyone in the world has to eat. See, we're all the same. That's not really going to create a strong bond across different cultures. One group believes in female circumcision and another group doesn't. The feelings that this generates will be strong and push people towards the groups with similar values.
The above example is extreme but it illustrates the point. Look at the high rate of divorce between interracial couples. I'm feeling pretty safe in stating that they're not divorcing because of female circumcision issues arising in their marriages. The differences between the spouses are much more mundane but like a pebble in a shoe they're irritating enough that they affect the quality of the marriage.