I attended and graduated from Crown College. The administration there did not forbid interracial dating when I was there. I do remember some couples that were interracial. The church itself has several nationalities represented in her membership.
I never asked anyone in charge why they required permission for interracial dating, so this is just conjecture on my part. I believe that there still exists in many churches (especially Southern churches) today the belief that interracial dating is somehow wrong. I have had people try to prove this insane doctrine to me by pointing to passages in the OT that forbade the Israelites from intermarrying with Canaanite tribes.
I do not believe that Crown College or Temple Baptist Church holds to this false doctrine. That being said, they may have put the requirement for permission in the instance of interracial dating because they anticipated possible problems arising when a child of someone holding to this doctrine begins dating against their parent's wishes. (I hope that sentence makes sense!)
I don't necessarily agree with that approach to the issue, but I do understand why they would have such a rule on the books. It is a bit of a pragmatic step.
I spent 8 years attending Temple Baptist Church and graduated from Crown College. In that time, I never heard one word about interracial dating. I remember reading the rule in the handbook, but the subject was never talked about officially. In my time there, I never heard Dr. Sexton mention interracial dating, much less preach/teach such a doctrine. I never heard any church staff or college faculty member ever mention the issue, much less teach a doctrine against interracial dating. I do realize that my not hearing of or observing it is an insufficient means for absolute proof, but I do believe that anti-interracial dating was not an issue during my time there.
I think the rule capitulates to the biblical ignorance of some prejudiced people, and therefore I do not personally agree with it. But racism is not an institutional problem there.
Why is this rule being tolerated? Because the students there do not have a problem with it. Interracial dating (even marriage) is not forbidden or taught against at Crown. They simply require parental permission.
---Disclaimer: I have no real "insider" information other than my observations from my time there. This is just my educated guess.