It would be safe to say the church at Galatia was primarily composed of gentiles.
Gentiles. The uncircumcised. Keep that in mind.
Well in mind. The act of circumcision belonged to what - gentile religion - or rather Judizers - keep that in mind.
Gentiles, not jews, served those who by nature are not gods. They didn't know God.
Gal 4:9 But now after you have known God, or rather are known by God, how is it that you turn again to the weak and beggarly elements, to which you desire again to be in bondage?
They weren't Jews. They were gentiles. Paul compares their situation to returning to the weak and beggarly elements they knew before.
Here is where your train of logic derails. You are shifting the focus onto the believers in Galatia - Paul is focusing on the false teachers and what they were trying to sway them to - return to bondage under the ceremonial laws and customs of the Judazers. These false teachers were not trying to sway them back into idolatry.
Gal 4:10 You observe days and months and seasons and years.
Whatever these were, they were NOT God's holy days. In the new testament there a specific greek words that are always used to distinguish and identify God's holy days. The word used for a holy day is (transliterated) "heorte". This is used consistently. Sabbaton or its derivatives is used to refer to the sabbath. Neither of these words is present here. Paul wasn't talking about the holy days.
This is not hard Doug, but you make it so. Compare to Col 2:16. The days are the Jewish Sabbaths. The months are the new moons; the times are the Jewish festivals; the years are the Sabbatical years. In observing these there was legal bondage to an obsolete system. As you've said over and again, these were primarily gentiles - they would be relatively ignorant of Jewish customs and holy days. Paul objected to Gentiles taking to them as a means of salvation. This is a very appropriate means to describe the Jewish calendar related activities to a non-jew. Furthermore, the word heorte is not found in this verse. It is used in Col 2:16 in conjunction with a "holyday" (the only translated occurrence in teh NT) in context with sabbaton , and 26 other occurrences it is translated "feast". That is a very weak argument to base you doctrine upon.
Circumcision
Observance of Jewish feasts and days of obligation as a condition of being a Christian
The nullification of the requirements placed upon gentile believers
So lets follow this through. 4:12-14 Paul reminds them that when he lived among them as a gentile, not as one under the Mosaic law. 4:21-31 Paul warns about the errors in following works over faith.
There was a sect of Judaism that was teaching that you needed to observe a bunch of man made regulations and commands to be "saved". Non-scriptural things.
Interesting that you choose to follow Paul's warning against Judiazers in Colossae, but ignore the same here in Galatians - very inconsistent - almost a pick and choose method of bible interpretation.
I think you would be well served to study Judaism currently and at the time of Christ and see exactly how much of it is based on tradition and not scripture.
I have done some reading on the Jewish customs and traditions at the time of Christ and the early church. Modern Judaism is removed from that era by thousands of years and the loss of the temple. Many bible commentators and scholars have done much more, and they unanimously recognize that the false teachers at Galatia were teaching that one had to become a Jew and follow ceremonial law and customs in order to be Christians. This is based upon a fuller study of Paul's writing, and in nearly every letter he warns about this. Something to keep in mind.
Bottom line here Doug, is that you erroneously interpret Galatians as Paul's letter by trying to have it focus on their behavior in gross contrast to what the book really addresses, and that is false teaching from Judiazers. Once you do that, you will see that your interpretation of that passage is flawed because you've taken it out of context. This is evident from the decision you are silent upon from Acts
Ac 21:25 As touching the Gentiles which believe, we have written and concluded that they observe no such thing, save only that they keep themselves from things offered to idols, and from blood, and from strangled, and from fornication.
They were to be free from the obligations of Jewish ceremonial law and customs. Pretty simple and straightforward and saves taking a lot of good scripture out of context.
You're mixing some things up. Paul knew that the Levitical priesthood was no longer in effect (see Hebrews) so all of the functions of that priesthood outlined in scripture couldn't be performed. Paul knew that the sacrifice of Christ was sufficient so no more animal sacrifices had to be performed. Paul recognized that, as you said, the Jews had instituted many customs and traditions that were non-biblical. Jesus railed against these non-biblical customs. In many cases these ideas and customs had been incorporated from pagan religions and thought.
Jesus and his followers were basically trying to get back to the religion once delivered, worship of the Lord without all the Jewish and pagan influence. They didn't intend to completely create a new religion. They didn't intend for Christianity to jettison everything the Lord had already delivered. They knew that that certain things were changed under the new covenant. I'll keep saying this till I'm blue in the face, but these things are listed in Hebrews and they're very specific. Sacrifices and the Levitical priesthood are the primary changes brought about by the new covenant. However, the first Christians kept and preserved things such as the holy days and the food laws. Historically you can trace when traditional Christianity officially outlawed sabbath keeping and other so-called "Jewish" customs. Mostly it had to do with anti-semitism and from a desire not to resemble Jews.