I mean, pro- or anti-Trump, you have to admit that he's at least symptomatic of divisive politics, right? It's probably fair to go one step further and say that he also embraces that divisiveness.
That's without expressing an opinion on the underlying politics.
I would say Obama divided the country more than Trump. Trumps approval rating among african americans is now over 40%. That's huge. To US citizens, Trump is less divisive in my opinion, but his character definitely sparks the opposite side into creating a new bread of louder and in your face divisive culture (Antifa, etc).
Altough I believe that to be true during the Bush years as the anti-Bush types were very loud and crazy. Now that many more people are online and are able to spread opinion via Twitter/FB/youtube/etc, the divisiveness from activists has gotten louder. Joe Rogan also observes this in how he describes the 2 minute tv news media culture where 10 people are trying to shout over one another to get their point in, and how that is a sign of a dying medium (being replaced by internet, long form discussion, etc). This seems like further proof that the traditional media is more divisive more than ever...it's the last breaths of a dying medium. Don't think that's true? Just watch local tv news in SF Bay Area and compare to a smaller city outside of a major metro (blue) area.
That's without expressing an opinion on the underlying politics.