Originally Posted by
-:Undertaker:-
The Obama administration and the President himself were under criticism within the United States for failing to properly denounce those rioting such as Ferguson and Black Lives Matter, excusing them or failing to properly condemn Police murders by these street gangs. As somebody who listens to a US talk show every night and has done for three or four years, this wasn't covered in the British press but was covered extensively in the US. Hence your apparent surprise at these attacks on his legacy.
Many Americans view Obama as a disgrace to the office of the Presidency for this and much more, hence why his successor got her arse handed to her in the Presidential Election. Of course, British media were in love with Obama (remember the gushing from the BBC compared with the constant sneering as George W Bush) so you're probably unaware of this controversy surrounding him.