Thank you. This is very carefully formulated and I have no quarrel with this way of describing the liturgy.
But then you say
[the Catholic Church is] offering sacrifices contrary to the one time sacrifice of Jesus Christ
If the Catholic Chruch were offering such sacrifices, that would have been indeed preposterous. But does it? Your careful formulation of the nature of the Mass does not support the cheap and untrue propagandistic caricature of what the Mass is.
Like Bishop Sheen, and may others said, your fight is against the caricature of the Church, in which all Catholics would join you if it were grounded in fact.
FWIW - and I know you will disagree, and that is OK - I tried hard in the first phrase to get it IAW Catholic teaching. However, when someone believes this ‘multiple participation’ results in multiple forgiving of sins, and that it is a requirement for forgiveness of sin as one goes through life, I think the Catholic Church in fact, if not in word, considers them multiple sacrifices. At a bare minimum, the Catholic Church teaches that God views the sacrifice of Jesus as an ongoing sacrifice, always before Him (since He is supposed to be outside of time, and seeing all times at once).
However, there is no place in scripture where it is described thus. Even when speaking from the perspective of God in Heaven, it is always ‘the Lamb that WAS slain’. Or it says ‘AFTER his sacrifice, he sat down at the right hand of God and waits...’ - indicating that either God’s nature involves a sequential perspective, or that God has completely shut up the sacrifice of Christ and refuses to look at it.
In practice, Catholics treat it as a repeated sacrifice. There are Vatican approved books talking about a repeated sacrifice, offered again and again - which I think more accurately reflects what the Catholic Church believes. I find the whole ‘re-presentation’ argument disingenuous.
That is why I sometimes speak of it two different ways. One is what the Catholic Church - which has had Hebrews stuffed in its face many times - SAYS. The other is what I believe the Catholic Church PRACTICES.
And even when one uses the first phrasing, I think it doesn’t appreciate what Jesus did at the cross. When it says he has made us perfect forever, that means he has forgiven our sins - if we have truly believed, and are born again as a new creation. If the ‘re-presentation’ is for remembrance and thanksgiving, as Eucharist suggests, then it is fine. If it is for atonement, then it misses what Jesus has done.