Isn't she Mexican? Why would she support a campaign that ignores her community's needs?
That's like saying, why would a male support feminism? Why would a trans women support gay marriage? An equality movement doesn't have to be built for you in order for you to support it.
She was right in that you dont need to use a hashtag in order to validate your activism or support for something, but what has she ever used her voice for? Also "picking sides" bit was messy. There should be no sides to pick. You should be able to acknowledge the disproportionate killings of black men by the police.
She's just mad the guys tweet exposed her hypocrisy. She shouldn't have responded.