The crux of the issue is, according to Roberts, that Judges are above the will of The People. He points out, by his own admission, though perhaps not by his intention, a fundamental flaw in our judicial system.

This is what Trump said that elicited the response by Roberts:

This Radical Left Lunatic of a Judge, a troublemaker and agitator who was sadly appointed by Barack Hussein Obama, was not elected President - He didn’t WIN the popular VOTE (by a lot!), he didn’t WIN ALL SEVEN SWING STATES, he didn’t WIN 2,750 to 525 Counties, HE DIDN’T WIN ANYTHING! I WON FOR MANY REASONS, IN AN OVERWHELMING MANDATE, BUT FIGHTING ILLEGAL IMMIGRATION MAY HAVE BEEN THE NUMBER ONE REASON FOR THIS HISTORIC VICTORY. I’m just doing what the VOTERS wanted me to do. This judge, like many of the Crooked Judges’ I am forced to appear before, should be IMPEACHED!!! WE DON’T WANT VICIOUS, VIOLENT, AND DEMENTED CRIMINALS, MANY OF THEM DERANGED MURDERERS, IN OUR COUNTRY. MAKE AMERICA GREAT AGAIN!!!

Emphasis mine.

Trump is saying here, or at least implying, that We The People have no recourse when a judge is evil. Note I am talking about the Judge, not their decision. We can't impeach a judge. We can't do anything against a judge. They are the law (literally) and are, at least in our current system, above the will of the people.

Roberts agrees:

The court has obviously made mistakes throughout its history, and those should be criticized, so long as it is in terms of the decision, really, and not ad hominem against the justices

You can agree with a Judge's decision, but only through a ludicrous and expensive process chock full of cronyism and self-protection. You can criticize only the decision itself, never the person (equal human being) we call "Judge," no matter how bad of a person they are, or how powerful their decisions are.

This systemic flaw has always been that way, from the very beginning of our historical record. In the Code of Hammurabi, for example, they had laws for almost everyone, even the King. The only people who were (legally) above reproach were the Priests, the very same people who wrote the laws. Of course at the time, the Priests were the Judges. This system of laws created (by intention) this class of people at the top of the hierarchy. Importantly, the King was said to be the most important person in their society, but in reality it was the Priests, controlling behind the scenes.

The more I look into things the more that nothing has changed since that Mesopotamian culture (in more ways than one).

For more than two centuries, it has been established that impeachment is not an appropriate response to disagreement concerning a judicial decision. The normal appellate review process exists for that purpose,

"The normal appellate review process" (a system of cronyism) is the ONLY "appropriate response to [a judges] disagreement". WE HAVE NO CAPACITY TO GET RID OF THEM, NO MATTER HOW EVIL THEY MAY BE.

To learn who rules over you, simply find out who you are not allowed to criticize.

Who are you not allowed to criticize? Judges.

Who rules over you? Judges.

Who wrote the law? Judges.

What can we do about it?

Nothing.

At least nothing Constitutional.