Because the stated rationale is logical, predictable and matches what the colleges have been doing. This outcome was widely predicted years in advance and would be happening even if Trump had never been born.
Even if were to accept those things as true, stating things which are true is not the only indication of good faith. It is a widely used tactic to use rules only followed by one side against that side. Example (feel free to replace "I" with "my supporters" here): If I believed that anything I did in my interest was acceptable, but you believed that you were bound to work in the interest of the public, then I could claim that you giving your son a government job was corrupt and you would be bound to defend that, whereas if you claimed giving my son-in-law and my daughter government jobs was corrupt I would just ignore you.
