I think the media has gone to great lengths to propagate this idea.
I don't think the President has done anything untoward since he took office, though his rhetoric during the campaign certainly was inflammatory at times.
The difference is where you stand on issues, President Obama had an anti-colonialist, apologetic for America's past outlook. His position toward business "you didn't build this, we did", his position towards race "if some white people have to suffer to accomplish this"...
There was a rising tide of anti-police vigilantism under President Obama, he would pardon efforts of BLM individuals for intimidating people at voting sites, for assaulting police, while condemning the police at every turn.
The President often seemed too tied to his former community activist/antagonist past, he could not leave well enough alone at ceremonies to honor fallen (murdered) police. “…there are real problems and a deep distrust that exists between law enforcement and people of color” - “We need to recognize that the situation in Ferguson speaks to the broader challenges that we face across the nation…”
Obama’s subtly inflammatory comments were not what the nation needed to hear at those times of extreme emotionality. With two or three sentences within a longer speech, Obama fanned the flames of racial discord.
While those comments by President Obama were brushed off or quickly buried by the media to minimize the negative backlash as swiftly as possible, the media has done the opposite for President Trump, they have magnified, taken out of context, and brought to hyperbolic climax the levels of racial strife whenever they could.
Trump and Obama are very different... one was a Harvard intellectual that had spent his impressionistic early years in Indonesia studying Islam (age 6 - 10(?)) he spent his formative young adulthood surrounded by the likes of Frank Marshal Davis, Reverend Wright "not God bless America, God damn America!" and "we need to make war against the white people" and Bill Ayers and Bernardine Dohrn, etc. etc.
The other was sent to a military school when young, he was indoctrinated into discipline, American ideals, went to Fordham and Wharton Universities, grew up entirely in America, surrounded by business, investing, real estate, etc. there is nothing radical about him.
One believes in Globalism, and that America isn't that special and needs to be brought down to an equal level amongst all nations, the other the exact opposite.