This is perhaps the most profound root of the problem. Leaving aside for a moment the fact that all of western civilization (including our very own Declaration of Independence and Constitution) at least purport to be based on objective reality, the rejection of the very notion of objectively based beliefs about the nature of humankind is, in itself, the very foundation of tyranny.
If one accepts the principle that all beliefs are merely subjective, then there is no foundation for the law other than subjective beliefs. The only question, then, is whose subjective beliefs will prevail over those of others. If one looks at, say, the Obergefell (gay marriage) decision, it is exactly based on subjective beliefs.
Not intending to be tedious about this, but subjectivism prevailing over long-established beliefs deemed objective, is exactly what Nietszche thought to be so destructive of a rational society. The “Death of God” about which he wrote was not meant literally. It was about what happens when long-held beliefs are swept away by subjective beliefs. It then simply turns into a war over whose beliefs prevail. Ultimately, it gets resolved by the “Superman” who is “beyond good and evil” and has the power to impose his will.
The 20th Century saw a lot of “Supermen” who swept aside mankind’s best attempts at reaching and holding objective principles, and simply imposed their own subjective determinations by force. If principles do not prevail, then force alone inevitably does.
It’s one of the failings of our time, I think, that people do not recognize the Judeo-Christian roots of vast segments of our law, seeming to think long trains of legal reasoning based on religion and natural law somehow emerged out of the heads of legislators and judges, like Athene springing fully armed from the head of Zeus. Laws as seemingly mundane and secular as the Uniform Commercial Code are based on Judeo-Christian principles. If you look at old cases, the judges even admitted it. Now they don’t, but they still apply them, by and large.
But the more our courts resort to subjective judgments, the less secure everyone will be.