This statement ignores the central thrust of the Abrahamic Covenant, which is summarized in Genesis 12:1,2. It promises that the entire world will be blessed by Abraham and his descendants. If God's holy inspired word is meant to be read only by descendants of Abraham, Isaac and Jacob, how is it that that very book says Gentiles are to be blessed through those very descendants?
We goyiim who love the Hebrew bible will go on reading and studying it, regardless of the exclusivity the poster expressed.
Gen 12:2 says God will make of him a great nation. The word used is "goy" which, in the OT, is translated no less than 143 times also as heathen, 30 times as non-Jews and 11 times as people.
It was not until Paul that the Greek term "nations" or better yet "tribe/tribes" (ethnos/ethne), the Greek translation of goy/goyim, began to be used exclusively for non-Jews.
Christians have fabricated a myth on top of a myth, claiming that not only was the OT written for them as well, but that somehow they have been "grafted" onto the Abraham's family tree and represent the "true" Israel.
When ZC told you the fact that reading the Tanakh by non-Jews is like someone reading someone else's mail, he was spot on: the Old Testament was written by the Jews, about the Jews and for the Jews only. There is nothing in the OT that says it was intended for the non-Jews.