The denigration of people to a non-human status because of their beliefs has a long history and has killed millions of people.

The reaction described in the video makes me want to dig a little deeper. People are motivated by intent or fear. As she did reach out to the mother, it most likely is intent. Look for something that would have a better outcome if a SJW persona is worn. Is she running for office? trying to join a club? working for a media outlet?

Try to connect face-to-face. I know the younger generation is comfortable with electronic messaging but the older generations tend to posture when even just speaking on the phone. My mom always had a "phone voice" until she knew who was calling.

Body language is more important when fear is the key factor, especially if you know the person well but even if intent is the motivation, the body will reveal more that a tweet ever will.

That's all I got... Leaving it open as this girl did is the best I think she could do. At least she didn't go apeshit and burn a cross on the woman's lawn. If the mom was willing to discuss the "elephant in the room", she may have better luck.