Thank you.
What justifies the statement that the law “binds only at the level that a normal citizen obeys it”? Because that reveals what the legislator intended?

My claim is that the authority of a government in a democracy (as opposed to a monarchy) comes from the public that elected it, and the public is what determines the government’s powers. If the public tends to ignore the law a bit, then that defines the force of the law, and therefore there is also no halakhic prohibition against doing so. I was always amused by the statists who view democratic government as a “monarchy,” and are strict about the law in every minor detail as if this were a Torah-level law. They also tend to learn the laws of how to relate to government from the laws of kings, which is another absurdity rooted in the same mistake. In a democratic government there are different norms for how one relates to a leader (you can laugh at him and disrespect him), and that is what determines things. It’s a ‘democratic king,’ and its laws are determined by the rules of democracy.

With your permission, I’ll try to go one step further back and ask: where do you derive the halakhic obligation to obey a person whom the public elected? Meaning: what obligates me to obey the public’s decision?

By reason. The obligation to obey the Holy One, blessed be He, is also because the public chose Him. At Mount Sinai we entered into a covenant with Him and undertook to obey Him. That same reasoning underlies all legal systems in the world that assume a citizen must obey laws established by society. And the logic is that a person is an individual who is part of society like a limb in an organism. So when society determines something, it is as though he himself determined it.

Is the obligation to obey morality also because the public chose it? And if not, what’s the difference between that and the commandments?

I didn’t understand where that assumption came from, and I didn’t understand the question.

The rabbi wrote that the obligation to obey the Holy One, blessed be He, is because the public chose Him. Is the obligation to obey morality also derived from that?

No.

What’s the difference? Why do religious values need acceptance by the public in order to be binding, while moral values do not?

You’re asking what the difference is, and I’m wondering what the connection is. Morality is a condition for the existence of society and therefore does not depend on undertaking an obligation. You don’t harm another person because you have no right to do so. You don’t need to commit yourself to that. It’s no accident that the Holy One, blessed be He, held Cain accountable for murder long before there was a halakhic prohibition against murder. And the Seven Noahide Commandments also did not begin with the Noahides undertaking them; they were imposed on them coercively, like a mountain held over their heads.

Eating pork also harms some value. Do I have a right to harm that value?

Yes, just as it’s permitted to a gentile. Only someone who took this mission upon himself is obligated in it. Apparently only a certain group needs to refrain from pork.