I'm sure there will be some assessments of the article by some with formal theological training. It's hard to understand where the writer of the article is coming from. He uses the term "replacement theology."
I do know that the Westminster Confession is covenant theology. The term "replacement theology" is a recent term, and seems to be used as a negative, by those who assume dispensationalism but do not understand reformed (covenant) theology. The only analysis is something along the lines of, "They believe the church has replaced Israel and God has no more dealings with that nation, and therefore they don't believe the promises God made to Israel in the Old Testament, like we do."
I now understand this reasoning is seriously flawed, both in assumptions and understanding of the alternative (covenant theology).
Covenant theology is not "replacement" really. It is expansion of the covenant God made first with Israel to bring forth a Redeemer through their physical line who would redeem people from every tribe, nation, kindred and tongue. That includes Jews and Gentiles, by grace through faith in Christ.
Dispensationalism divides up God's plan of redemption in both time periods and ethnically. The system used to mean God did redemption differently at different periods of (man's) time. It implied God's people in the Old Testament were not saved by grace through faith in Christ. Now, that has been challenged and most back away from that and it only means separate plans of redemption for those who have some Jewish ancestry from the Body of Christ (the Church).
In dispensationalism, that used to be an eternal separation based on "earthly" promises to the people of Israel, and "spiritual" promises to the Church. In that system, it was never clear and there is a lot of disagreement as to what happens to people who have some ethnic Israel descent and who become Christians. Dispensationalism is backing off the "eternal" separation part now as it is challenged and the two separate groups ("Israel" and the Church) get together later in Heaven, according to the latest majority dispensational report.
"Replacement theology," as the author is using that term is not what happens. Nothing was replaced. God always planned to redeem people from every tribe, nation, kindred and tongue through faith in Christ.
Kim Riddlebarger's book, A Case for Amillennialism will be helpful in explaining this (in the context of the more narrow millennium issues).
It's a bit difficult to comment specifically since I can't seem to cut and paste.
My initial reaction is that the person writing this is a typical conspiracy nut involved with a cult of some sort. It starts with sloppy scholarship (the battle if Issus wasn't in Macedonia) and quickly moves into smearing mainline scholarship, like putting "christian Bibles" in sneer quotes.
Then he moves on to denounce the ecumenical councils, which we Reformed folk largely hold to, and he whines that they weren't Jewish enough. The council of Nicea is trashed because it rejected the Jewish roots of Jesus.
Augustine is rejected as an example of "Gentile" church leaders who rejected the Jewish roots of Christianity, and the obligatory reference to Luther and the Reformers spreading Jew hatred isn't forgotten, naturally. And just as naturally he takes a jab as us, since covenant theology leads to "replacement theology". Covenant theology is "too simplistic" and we're treated to several examples of our stupidity, and we call God a liar for changing His mind.
Half way down the first page he says covenant theology is dangerous and leads to killing Jews.
I then scrolled down to the end, where we're told to stop being arrogant and support Israel politically, which is of course the whole reason the article was written.