When I said converting christians, the jewish christian was implied. So yes, I understand. Perhaps you might be thinking about how nowdays when many christians want to obey most of the old testament law values, and being grafted onto the tree that was Isreal, enslave themselves to the law and trod afoot the grace given to them in Christ.
No, I am not referring to Gentile Christians trying to latch onto a Jewish following of God's law. That statement should be plain enough.
For a Jewish believer on Christ Jesus, there is nothing wrong with their trying to keep to God's laws that our Lord Jesus did NOT nail to His cross. Our Lord Jesus did not nail all... of God's laws to His cross, I hope you understand.
Thing is, a Jewish believer should not practice the parts of God's laws dealing with what Christ nailed to His cross, like the sacrificial Levitical Old Covenant worship and those things associated with it. Nor is the Jewish convert to Christ Jesus to try and force others into a ritual keeping of feasts, sabbaths, etc., in order to be saved by our Lord Jesus. But there is nothing wrong with their keeping of sabbaths and such, just as long as they do not link it to Christ's Salvation which is by Faith, and not works of the law.
Our Lord Jesus did not nail all of God's laws to His cross, which is why Col.2 states what was, i.e., the 'ordinances', ritualistic things especially to do with requirements under the Old Covenant.
Not every law God gave through Moses is that Old Covenant. That's why many Christian Churches today still recognize the Ten Commandments, and God's law against thefts, murder, rape, incest, perjury, lying, witchcraft, etc. Obeying those things is CHRISTIAN Doctrine per Christ and His Apostles, not Jewish doctrine.
The Judaizers were trying to require Gentiles to get circumcised, etc., to be saved in Christ. Some of them still today think to try and lord over Gentile believers on Jesus Christ, and some of them think they only have the 'key' to Salvation just because God first gave them the covenants and promises. It's those kind of things they need to be rebuked in Christ for when they practice that upon others.