I'm totally for it.
Granted, that could be because I am very attracted to men not of my race. In fact, it wasn't until high school that I started finding men of my race aesthetically pleasing. Before that, nothing.
And even now, I'm pretty sure I still find more men that aren't my race more attractive than those that are.
But in spite of my bias, I don't see a reason why not. In fact, it pissed me off once when my mother--who said this to all my siblings--pretty much told me that we could date whatever race we wished but that she wants us to marry inside our race. I blurted out that I might as well not get married then which made stuff awkward for a moment.
We're better now. Mostly I think all the men she had long relationships with were in our race and all basically... weren't worthy. Don't believe she'd really do it but it won't bother her anymore.
But yeah... there's no reason to be against it at all to me. I don't understand why people would.