It’s a judge, in court displaying that he is supportive of a very outspoken misogynist, transphobic, xenophobic wannabe dictator.
In what way is that a fair trial? If you don’t happen to like hateful dictators, he’ll obviously be biased against you. If you happen to like people like trump he’ll be biased in your favor. If you’re neutral, then you’re worse than an active enemy to him.
What if the judge wore a hat like this, then displayed it on his desk:

And you just happen to be a slaughterhouse operator on trial for not paying insurance or something on time?
Seriously.
Impartiality is important.