The Passover Seder is a Jewish celebration. During the 'church age' --that period of time during which God declares there is neither Jew not gentile-- Christians, those members of the Body of Christ, are not celebrating Jewish Seders. In submitting our will to God, being born again from above, we acknowledge that we are incapable of keeping the Law the Jewish celebrations amplify.
This is one core reason why the imagined drinking of the real blood of Jesus and eating the real body of Jesus at catholic Mass is such a blasphemy! WE ARE THE BODY OF CHRIST, so eating His body in a catholic wafer is nonsensical because We ARE the Body Of Christ by HIS SPIRT in us. By not acknowledging that WE ARE THE BODY OF CHRIST, catholic mass does not rightly discern the body of Christ thus the priest is feeding not blessing but damnation to the sincere adherents!
We who are born again are celebrating a remembrance of what our Lord and Savior did for us. Eating the bread and drinking the wine offering, we are identifying with the death of ourselves on His Cross, where He sacrificed Himself for us. He went where our sin nature says we should be, but instead, we remember that He went there for us. Thanks be to God. With His resurrection we are assured that the Promises of God cannot be diverted.
It seems to me you really do not have a good answer. Let's go with church age though as that seems closest. I see one plausible explanation. The one holy catholic apostolic church bound that the Body and Blood be celebrated and memorialized daily in the Mass rather than annually in the Passover Seder. And I say also unto thee, That thou art Peter, and upon this rock I will build my church; and the gates of hell shall not prevail against it. And I will give unto thee the keys of the kingdom of heaven: and whatsoever thou shalt bind on earth shall be bound in heaven: and whatsoever thou shalt loose on earth shall be loosed in heaven.
Matthew, Catholic chapter sixteen, Protestant verses eighteen to nineteen,
As authorized, but not authored. by King James
... we acknowledge that we are incapable of keeping the Law the Jewish celebrations amplify.
Okay, the Law exposes sin. A Protestant who rejects the Real Presence in Orthodox Christianity could still keep the Passover annually as an everlasting memorial or is one forbidden to protest by his denomination, sect, or pastor ? Do you think Christians are part of the commonwealth of Israel or not ?