We're asking why black face causes grief? 9/11 was 12 years ago; a bunch of people are alive now who still remember the hurt and the pain and the shock of the incident, who lost loved ones because of it. What has blackface done to anyone living now? Do we still live in a society where blackface is being widely used negatively? It's like when people demand justice for what happened to their ancestors even though the world is a different and much more tolerant (on average at least) place now.
And those videos aren't helping your argument because it's just showing us that people did not go into outrage over black people pretending to be white.