Sometimes the answer to a question is the simple fact of the obvious truth. In this case, it would be; because they can. That fact is clearer when you know that many more mixed marriages are occurring between blacks and whites of all social strata since laws, both secret (bad things will happen to you, financial and physical) and on the books, have been relaxed. However, you don't need a statistical analysis to know that as a rule, even though they can, they don't.(just more than before) Among your group how many mixed couples are there? Very Few?
It should not be overlooked how much allure is lost when something becomes easily within reach and ordinary to see. The everything for love, bucking the system and the whole world, something so out of the ordinary as to elevate you more than the norm, is gone.
Eliminating all that, why would black men marry white women? Several reasons come to mind.
1. They think that they are prettier, so they sought them out.
2. They think that they are more feminine(easier to get along with)so they sought them out.
3. They just happened to fall in love with them. or the white woman sought the man out.
4. They think that they have more money and are more willing to spend it on their significant other.
5. They think their children will be prettier.
6. They perceive them to be smart and to have an inside track in the business world.
7. A combination of several of the above.
Personally, I just prefer black women. Obviously, most black men do.