With every new lie he tells or every new horrible thing he does, his supporters are forced to embrace it. And it just compounds. If they question him now, that would mean they'd have to question the hundreds of other things about him they've accepted.

So if he says "the sky is green" then they have to accept it as fact. Because if they question it, then they have to question if he told the truth about getting a fair trial, and then they have to question if he actually tried to cover up sleeping with a porn star, then they have to question if he slept with a porn star, etc etc all the way back for at least a decade. It's much easier just to accept the latest small lie than question everything you've believed for so long.