What about the Truth said:
SHT, you have missed the big point that answers your question. I think you were as many others were, children of parents that came into the WCG. The majority of this group could never completely embrace what their parents believed and it was to no fault of their own that they were not exactly like their parents. The big dynamic that you have missed is the calling from God. The same calling that pushed, pulled and in some cases dragged themselves into something they had no real desire to get into and went against their sound reasoning of I have better things to do in life.
First, you are correct - I am from a lineage in the Church that started with a baptism tour by McNair/Meredith - a long, long ways back. I do have to address your statement of "The Calling from God" - a "Calling" that pushed, or pulled, or dragged people into the Worldwide Church of God. This in itself is a whole article and research to get into at another time, and one I intend to get into, but that's for a different time to break that down. The big questions have to be:
A) How are we certain that that "calling" is actually from God? Could there be an alternative explanation?
B) What evidence is there that such actions would be God-ordained?
These are the primary questions at the root of your argument as to the large point to the major question here. We have to deduce and determine, factually, that the actual reason why people were "pushed, pulled or dragged" into the Church was because God determined it was to be so. This must be done using fact, evidence, historical truths, and personal reasons for each individual case.
This calling or strong urge then led to accepting the reality that the wages that they had earned from sinning was death. This now led to the accepting that a perfect son was sacrificed for us and with the act of baptism and the acknowledgment that now having Christ indwelling in a person, you could not now expose Jesus Christ to sin. So the Sabbath, which the COG calls the test commandment and is of the 1st five commandments that relate to the worship of the Father becomes a desire to be kept because it was made holy and God says He wants that person to convocate with him and like minded people. The same applies to the Holy Days. These acts of keeping the Sabbath or Holy Days are physical acts expressing what Jesus Christ called the greatest commandment - to love the Lord thy God with your whole heart soul and mind. Many of the people that remain in the COGs count it a blessing to have to keep 1 day in seven and 7-14 other days with God and with those begotten of God because they get to start doing now what they hope will be in earnest in the near future - the return of Christ and the eventuality of eternally dwelling with God.
This is the bubble within what you call Armstrongism and is the bubble that has perplexed you personally. You have asked how could God call people into such an error filled organization or how could their be true Christians in the COGs. I don't have a direct answer to those questions but it could be that god wants to show the world that a small group of people in the midst of much error and evil can acknowledge love and worship him when most on the outside say it is impossible.
You state first that
A) The wages that they had earned from sinning was death. No argument on your point. I think that that is something that all people who claim a belief in Jesus Christ believe. This isn't at first a major differentiator.
B) You state that there is an acceptance that Jesus Christ died for us and with the act of baptism we could not now "expose Jesus Christ to sin". Let me stop here. Scripture says Jesus Christ became sin for us, in our place. There's a big difference between "exposing Christ to sin" - we all our sinners, only saved by grace - and Christ becoming sin for us and dying for us in our place so we can then be reconciled to God through his death and life. Therefore, this statement you make about "exposing Jesus Christ to sin" is redundant, because Christ has already become sin for us.
C) You state that this desire to "keep the Sabbath and Holy Days" is the main thrust of holiness, physical acts of expressing what Jesus Christ calls the greatest commandment, to love the Lord. Here's the problem. When the focus becomes physical acts to show love to God, the actual spiritual acts that constitute daily life and living in the Spirit of God become secondary and less important. Historical and present truth shows this to be the case. The emphasis of Armstrongism must be spiritual first, not physical - whereas Armstrongism reverses this and makes it physical first, then spiritual. The heart might be in the right place, but the batteries have been put in backwards.
D) It may be true that the Sabbath rest familiar to the COG's of one day off may constitute a blessing to many. Many Christians also enjoy the Rest of God by the Indwelling of the Holy Spirit all the time. I'm not blemishing your belief and your understanding of the seventh-day Sabbath. I am pointing out a difference of opinion that has happened since the conception of the Church, a difference starkly polarizing now as it once was between Jew and Gentile. As Paul said, it is a matter of preference. You are stating here, that the main people in the COG Sphere of Armstrongism have sided with the Jewish side of the argument, and have lost favor of the Gentile persuasion of the argument. You may have a solid point here, but it must be verified as to if the calling was actually from God, or if the "calling" was simply a siding of agreement with Paul, or agreement with the more Jewish-centered Christians in the whole argument of question.
E) I'm not doubting there are true Christians in the COG's. Christians are people, not any corporate Church. God meets people where they are, and works with people personally. I don't believe I've ever stated I don't believe Christians are in Armstrongism. I do, however, fully believe Armstrongism as a whole is NOT Christian as a denomination or organization - though again, I believe there are Christians who go to ACOG Churches that do have the Holy Spirit.
These called out ones understand when they read Paul who tells them to see their calling or make their calling and election sure. Unfortunately these same people equate their calling to the entity they were called to and can't see right now where the truth has been mangled and trampled.
Selective reading of Paul is pretty common in the COG's. It's looked through a filter, a lens, that is only read through the delivered message of Herbert Armstrong. The entire context of Paul's writings in the NT constitute a clear picture of what is required to make a calling and election sure. Armstrongism dilutes this message completely.
Although these people are in a bubble it is still permeable to the appalling conduct of their leaders which is most unfortunate. Most of these people are not going to leave until something big happens. Hopefully that big thing is what they are waiting for - God in their very midst.
Here is the big dilemma. Where is God in the appalling (that's putting it mildly) conduct of their leaders? We even have illegitimate pastors out there who have not even been ordained trying to run a sect! Every type of atrocity is out there in Armstrong Churches of God way out in the open. When one focuses on Jesus, totally and with pure focus, then God will be within them and work through them and make change from the inside out.