Does this mean the church, or the Lord's Supper itself, is a man-made invention?

This is the fair worry at the bottom of the whole piece, and it is right to voice it. If the schedule is man-made and the mediating office is man-made, it can sound like the essay is dismantling the Lord's Supper itself, even the church, and calling the whole thing a human invention. No one should nod along to that without checking.

And you are right to defend the cup. It is not a human contrivance. Every word Yeshua (Jesus) spoke over the meal was already old, the thanks rising to the Father, the flesh named as offering, the blood quoted straight out of Sinai (Exodus 24:8), the covenant promised by name in Jeremiah 31. He invented nothing that night. He kept an appointment.

You may also feel the tension the piece is holding: that you can love the table dearly and still have inherited a way of keeping it that grew up long after the upper room. Both can be true at once.

Here is the distinction to set down clearly, because everything depends on it. What is man-made is not the cup; it is the machine assembled around the cup over centuries. Trace the four moves the essay names: a memorial meal among friends hardened into a sacrament requiring administration; the shared table relocated to the front of a room; the friend who passed the cup replaced by an ordained office-holder; the whole thing housed inside an institution. Each was done, mostly out of love, by people who cherished the table. The love was never the error. The machinery was.

And when you lift the machine off, nothing that mattered is lost. The cup is still the cup, still His blood, still the new covenant cut once, 'once for all,' and finished (Hebrews 9:12). It is simply no longer a sacrament dispensed to you from above, but a covenant already cut for you, already yours. That is the larger thing the smaller machine was obscuring, not a smaller thing than what you had.

Do not take it from me. Read Luke 22 and Jeremiah 31 and mark how much of the cup is quotation, not invention. Then ask which part the piece calls man-made, the covenant, or the management around it.