I’m not sure if the “Hebrew Roots” people are all members of an Armstrong cult. They have definitely an overlap, but Armstrong taught a lot of things.
For example, Armstrong believed that...
... biblical truth had been lost from the first century and rediscovered by him in 1927. He wrote about himself as the Elijah who would preach before the second advent of Jesus Christ. He also taught that he was unique in the human race as Christs new Apostle and that he had restored essential truths to Christianity. He championed his work in gloating terms... saying, I candidly feel it may be the most important book since the Bible! (Walter Martin, Ed. Hank Hanegraaff, The Kingdom of the Cults, pg. 482).
From Armstrong directly:
I know of no other who has ever become a founder of a religion... who ever came into the truth the way God brought me into it... God brought me through a process that erased former misknowledge and, as it were, gave me a clear start from scratch. I wonder if you realize that every truth of God, accepted as truth doctrine and belief in the Worldwide Church of God, came from Christ through me, or was finally approved and made official through me... I was appointed by Jesus Christ, the head of the church. (Herbert Armstrong, Personal From... The Plain Truth (Feb. 1967): 47.)
On interpreting the scripture, it was like a jigsaw puzzle that must be assembled piece by biblical piece... and since before AD 70, it has been entirely suppressed. (H. Armstrong, How far can you get from being a Prophet of Doom? The Plain Truth (Oct/Nov 1977): 3.)
Armstrong on becoming “God personages”:
By a resurrection, we become born God personages personages just as our God the Father and Christ the Son! We shall have the entire universe put beneath our feet (Hebrews 2:8). (Herbert Armstrong, The Plain Truth (September 1980): 40)
He also taught Brithish Israelism, and even claimed that he was a descendant of King David on his mother’s side.
Some of the “Hebrew Roots” people might fancy themselves as a brand of Messianic Jew, who also deny that Paul is a legitimate Apostle. They might be Modalists as well, in the ones I have encountered.
Not to confuse all Messianic Jews for these sort. But some of them who claim to be “Messianic Jews” make these sorts of arguments, but the nature of their heresy is different from Armstrong.
Like I said in my post, Im not that familiar with either cult but had just been doing some research as this thread was posted that indicated there was a tie of some sort. This Herbert Armstrong, is he somehow related to Garner Ted Armstrong?