It's not just Obama, because this phenomenon is global.

Race relations deteriorated because (thanks to the internet) people were able to get access to crime stats and psychology and biology literature online. The Left realised their planned mixed-race utopia was under threat so they have since gone insane with race-mixing propaganda and affirmative action'ing their allies into positions of influence. Notice how they no longer debate the science and stats on race? Now they just go for straight up de-platforming.

This has red pilled even more people because it's so jarring to their experience of pre-2010. Even my normie wife now yells at the TV screen when she sees forced WFBM couples featured in the show she's watching and the majority of the ads.