I’m going to treat this as a question asked in good faith.
On principle, every president deserves to be “given a chance”. Campaigns can be fraught, and governing is a different ball game. There is a peaceful transition of power, and the new guy gets a shot.
But yes, something is different this time. As you acknowledge, Trump is a thoroughly unpopular winner. He lost the popular vote by a rather wide margin (only President Rutherford Hayes lost the popular vote by more) and he has the lowest popularity rating for any incoming president since… well since ratings were invented. By all accounts, he has the exact opposite of a mandate.
Any candidate in such a position cannot act unilaterally. They must build bridges. They must prove they can be a president to all Americans. They must begin their presidency by reaching out to shake hands with the other side of the aisle and promise to work together.
There were two months between inauguration where Donald could have done what so many people insisted he would do: become “presidential” in demeanor. And in his first days in office, he could attempt to bridge the divide.
Of course, we know now that Donald chose not to take that opportunity. He made extreme cabinet picks. He threw a tantrum about his inauguration attendance. He has lied about voter fraud. Gag orders on government scientists, pulling ads for health insurance enrollment that had already been paid for, the wall, alternative facts — the list is already very long and it hasn’t been a week. He has been his most belligerent, narcissistic self. He won on a minority, and has had decided not to try to turn that into a majority.
Maybe Donald can “get away with it”, whatever that would mean. He could be completely free from the traditional idea of political capital, and manage to govern without majority support, instead relying on unilateral action and bullying. He’s not popular, and he has chosen never to become popular.
The consequences: four years of protest, resistance, and a great deal of national divide. Donald has forfeited his honeymoon.