I understand. I truly do.
The reality of some family groups, however, is that there will be differences in social, political, religious and economic beliefs. What are we do to? We can choose to associate only with those who share our beliefs. But that is hard to do when family is involved because we don't choose our family members.
The whole racism thing *is* offensive. Believe me, as a minority I can understand that. It is definitely difficult (it takes a saint, really) to be nicey-nice with a bigot who harbors prejudices against you. Yet, the only way to affect any real change within her and the family is to live to prove them wrong.
But you need to do what feels right to you. You must honor yourself and your truth.