You give them more credit than they deserve. The truth is, those 53% actually do think Trump is better that Lincoln, for many good reasons.
Firstly, Trump is the current Republican president. That alone makes him worth far more than Lincoln, no matter how else he may compare.
However while the current president having an 'R' next to his name is by far the most important thing, Trump is much more than that. Almost everything he has done fulfills the desires of republicans in one respect or another. From stacking the courts with conservative judges, to denying global warming, to trade wars with China and building a wall to keep out 'undesirables', Trump's actions have aligned with conservative wishes more than any other president in history - no wonder they all love him.
And many of the things we think make Trump a bad president are what they think make him the best - racism and xenophobia, sexism, putting down anyone who is not sufficiently obsequious, constant lying and then doubling down when caught out etc. - all stuff they wished they could get away with openly but couldn't because libruls would see them doing it.
Finally there's the pièce de résistance, it triggers liberals. Even the stuff Trump does that they normally would disapprove of is good, because it gets liberals upset too. Conservatives don't need to troll pollsters or anyone else, because Trump is their troll!