Would you have felt the same if John Boyega had expressed a preference for dating only white women?

I don't have a problem with people having preferences, but you cannot on the one hand argue something is a valid preference when it supports your world view and simultaneously an example of white supremacy when it doesn't. Adults can date whomever they like and for whatever reason they like.

If that reason is based on skin colour then so be it - but it's racially prejudiced either by default or design.