Modern rabbinic jews are not the same as the Old Testament Jews. It's an entirely new religion. Christianity and the Church are the continuity of Old Testament Israel. The Church Fathers agree with this 100%. I also highly recommend Religion of the Apostles by Fr Stephen De Young.
There is a fundamental truth that sin blackens the soul and is a form of self harm. Some much more apparent than others. I feel your pain at being denied the Eucharist at a Catholic mass but there are reasons. See 1 Corinthians 11:17-34, also James talks of confessing our sins. The Church comes with the duty to follow the commands of Jesus laid out in the Catechism and to be inducted into it. It has been done that way from the beginning. What must please the Lord is that you are preaching some of the most important parts of the faith. You must eat of his flesh and drink of his blood (See John 6). It is the pure sacrifice offered by the nations (See Malachi 1:10-12)
Pastor, there was no open communion practiced anywhere until the last hundred years or so ago, let alone in the Orthodox Church. We can certainly get into the theological reasons why closed communion is correct, but the bottom line is that everyone in the history of Christianity did not get until wrong until contemporary evangelicals came along. With all due respect, this is an issue where you should humble yourself and submit to apostolic teaching rather than your own understanding. I certainly have had to do the same on my own journey.
