Trump did nothing to start the division. It started a long time ago and Obama had a unique chance to heal the county and he made it worse.
It was not Trump or the republicans who are divisive.
1. they started talking impeachment before he was even inaugurated,
2. Countless Dems skipped the inauguration
3. They did not accept the results of the election and peddled false stories for three years
4. It was not the republicans who treated Kavanuagh horribly
5. it is not the republican's who stoke racial division.
Quite honestly I think most people on the right dont give a shit about skin color, sexuality etc etc etc until it gets thrown in their face constantly and we are bombarded with the message that if we are white we have privledge and are inherently racist.
The left thrives on division because it keeps a segment of the population thinking they are the victims and nothing is their fault and only government can fix things and help them. The right loves equality of opportunity - fairness, unity.