Lacking a viable court system is the ultimate explanation. We do NOT have the same conditions as we did in the desert - we lack the Tent of Meeting on which God's presence rested, we lack the priestly breastplate and sacrificial system, and we lack a prophet like Moses. How are conditions the same exactly? Reducing it to "enforcers etc" just means you don't understand the system because you rely on archetypes not on people. Authority is not a matter of having a title. You admit we have no "real prophets" and yet you say that we have the proper authority. You are simply wrong and it isn't your legal system to decide what is required. You can't claim that a system you don't understand has to exist because you, in your ignorance, say it does.
You scan some of the 613 which I posted because you asked for proof that some of them are sourced in Deuteronomy. So I proved my case. Now you look at them and decide that some shouldn't count as part of the 613. Funny thing...you don't get to make that decision. You want to create categories based on the conclusion you want to reach. Feel free. It is a waste of everyone's time. It might be useful in your religion, but not in Judaism. You don't get to walk into Judaism at say that your personal sense of how things should be trumps the religion that has been established for thousands of years. You say to "think like a lawyer" and yet you only use that process to rationalize your disdain for black letter law. You stick to the basics, but only to things that YOU decide are the basics, ignoring anything you don't like and finding a way to discount it. That's not a lawyer thinking -- that's someone who doesn't respect the entire legal code and picks and chooses.
As to what is binding or required of you, all of them aren't. You aren't Jewish. Judaism knows that Jesus is irrelevant (if nonexistent) and your personal affection for one of the many, many commandments is simply adorable. Just adorable. However, it is also irrelevant.
Whatever my objective stance is regarding Judaisim, my subjective stance is that I am grafted-in as a Christian.
Breastplates were never necessary to enforce the Law. A tent of meeting was not, and The Temple was not. You seem to be prioritizing the most odd or oddball things which precipitate ENFORCEMENT, which is only historically only stemming from primarily the Word of God come unto men or a man. If God TELLS you to bean this one or kill that one, what's a tribal leader or prophet to do? The Pharisees and Sadducees world view was that the Word WRITTEN allowed them access and by the way compunction to repeat the stoning laws of old. Not a court as we know it today or the U.S. judicial system.
This basic concept was true from Abraham to Jesus. They took the adulterous woman to Jesus to see what he would say, KNOWING already he was gonna contradict their normal judicial punishment.
But the way he DID IT, was key and the reason why no man could speak against him. He said for the man without sin to throw the first stone. This was never a requirement in Torah or any of yours mentioned. But in the New realm of Covenant, this would be now true. The Law has fundamentally changed, and a stone for a sexual betrayal was no longer required.
As for my adorable adherence to the Law...
And my adherence, sir, to the Ten if done in Germany would have stopped the Holocaust in it's tracks. The Ten is not only for the Jew but for every man born of a woman, and his wife and anklebiters. A spiritual man of ANY religion knows these in his heart, and possibly in letter. Thou shalt not covet or steal. Thou shalt not murder. And the Ten was encapsulated by the SIMPLE Golden Rule from Jesus' mouth. Proclaimed by more than one guru, or sifu, or pastor, or imam.
Hint: However much you say I'm not a bona fide Jew, my God is your God, and I love this God very much, AND follow His Commands, the 613 being those extracted, from men. Call it adorable, I consider it life and death. FEAR of God is not one of the ten, rather a direct implication of all the Ten, just as the first command unto a man, Adam implied fear to break it.
It is not a basic Command since it is the beginning of Law and LOVE is the mechanism which turns all Law in adherance to God, OVER fear. And THIS God is not like your mommy or your daddy who might could overlook your sins. He is the Almighty and fearful to behold, even unto your own destiny being a thirsty one, by which you are so very regretful you did not love Him more. To love THIS God, is to fear how tenuous this relationship in Covenant really is.
So then what is the First Law, you know it already. Shema, to love God with all. The 613 insisted upon may actually degrade the First Law since Love, not fear will rule among the remnant. Knowing God exists is really moot, and only for the Greek philosopher. And on...and on.