Our Lord and St. Paul are speaking against the tradition of the Pharisees, and Paul specifically against the notion that non-Jews must accept the law.
Absolutely incorrect! The church at Colossae consisted of newly converted, previously pagan, Greeks. They had no inkling of God's holy days, festivals and Sabbaths prior to their conversion. Paul is instructing them in the observance of the ordinances....."Therefore do not let anyone judge you by what you eat or drink, or with regard to a religious festival, a New Moon celebration or a Sabbath Day."
Why in the world would Paul waste his time explaining something to these folks if he then wanted them to ignore it?
Explain Matthew 28:1 to me.