The obvious question is why is Twitter doing ads at all. The obvious answer is that Twitter is struggling. Its obnoxious attempts to capitalize on Black Lives Matter's racist violence, particularly the video's references to Dallas, are an echo of how Twitter used the Arab Spring to promote itself.
Watching the ad though you get the impression that the main reasons to use Twitter are sports and social justice movements. That's how Twitter would like to be seen at least. It's not however the reality. And it's losing control of the social justice conversation despite renewed censorship.
In fact, from July 5 to July 7, fully 87% of the uses of #BlackLivesMatter on Twitter were favorable, compared to 11% that were negative.
However, following the attack on police officers in Dallas that began late on July 7, the tenor of the online conversation changed dramatically. From July 8 to July 17, 39% of tweets using #BlackLivesMatter were opposed to the movement, compared to 28% that were in support and 33% that were neutral.
On July 17, the day the attack on police occurred in Baton Rouge, Louisiana, two-thirds of the tweets opposed #BlackLivesMatter (67%) compared to 26% that were positive and 6% that were neutral.
So that just means more censorship.