The MSM didn't like that the right side of politics had begun referring to him as this. So they pushed it onto Trump.

https://www.washingtonpost.com/opinions/divider-in-chief/2012/05/03/gIQAMPR0zT_story.html

https://www.amazon.com/Divider-Chief-Fraud-Hope-Change/dp/1621570118

https://clashdaily.com/2017/12/divider-chief-heres-obama-divisive-president-history/

http://www.truthdispatch.com/barack-obama-the-divider-in-chief/

https://www.washingtonexaminer.com/divider-in-chief-obama-leaves-nation-more-divided-than-bush

Truth Dispatch:

"He made the claim that there were some people who do not like him because they do not like the idea of a black president, and that there are some black and white people who voted for him because he is a black president."

This is unfortunately true. People did vote for Barrack Obama primarily because he was black. And, there were people who did not think a black man should be President.

I do not think the majority of Trump Supporters are racist to the degree that they would never vote for a black president. There certainly are Trump Supporters who would vote for a black president because he was black (and a Republican.) I don't think making these statements are as divisive as comments made by both Hillary Clinton and Donald Trump during the 2016 campaign.

Obama, for the most part, was pretty eloquent. That doesn't make him perfect nor prone to saying stupid shit; but he was pretty clear that he wasn't just the President of his Voters, and those who support him, but everyone. That is not something I can easily attribute to Donald Trump.