Mixed kids... Not sure how to take this

Me and my mom got on the topic of interracial relationships and she asked me "what is so wrong about wanting to keep a certain race alive? What's wrong with whites wanting to keep their race alive and blacks wanting to keep their race alive?" She said personally she would never have a mixed kid and wants to keep the white race alive in America. But my boyfriend is middle eastern, which could fall under different races... she seems to be supportive of my relationship but that comment made me question everything. So my question is how would you take that and feel? 
For the record, I don't care if anyone approves of my relationship I absolutely love him and don't see a problem with mixed kids of any race/ethnicity. But still I am concerned on her views towards my relationship since she would never blatantly tell me she disapproves, if she did.