I think the explanation is in the description of the problem with the members of the church in Smyrna that we read of in Rev. 2. They were circumcised in the flesh but not in the spirit and John said Revelation 2:9 I know your afflictions and your poverty—yet you are rich! I know about the slander of those who say they are Jews and are not, but are a synagogue of Satan.certainly not the law properly understood & used lawfully. but the law, properly understood, is spiritual and testifies of Christ.
there is a great mystery here; for some reason circumcision is part of the law, but Paul is able to charge by the Spirit that accepting it physically is falling from grace. this is really astonishing! at least it should be! so we have to properly understand how that can be so in order to understand how the law & its relation to us as having been immersed into Christ is properly understood. this is only one example of many, but it's indispensable, and useful as a test because scripture is so clear about it: if some understanding of the law and its application to believers can't explain circumcision, then it can't be right; it is evident immediately that it must lack something.
The order to perform the ceremonial law was never meant to be the law in itself, it was to lead to obedience of the spirit of God that is the real law.
When we go back to the OT instructions about the rituals, we need to read them to determine what the spirit of God as the law was. The information is there and so very useful to us. But reading of the ritual alone is nothing and was never meant to be the actual law.