Was Colossians written to counteract false teachings?

Answer 1

Yes.

False teaching which became known as Gnosticism was beginning to threaten the church at Colosse. The Gnostics prided themselves on their knowledge (Greek, gnosis). They claimed to have information superior to that of the apostles and tried to create the impression that a person could not be truly happy unless he had been initiated into the deepest secrets of their cult.

The letter to the Colossians contains the most severe warning against unguided human intellect or non Biblical philosophy:

Beware lest any man spoil you through philosophy and vain deceit, after the tradition of men, after the rudiments of the world and not after Christ -- Col 2:8

Answer 2

That was not the real reason for the Epistle to the Colossians. Burton L. Mack says (Who Wrote the New Testament) the letter to the Colossians is not an authentic epistle written by Paul. He says that, written under Paul's name sometime during the 70s, it shows that the authority of Paul could be used to address a sectarian conflict that had arisen in Asia Minor.

Answer 3

Yes, Paul is arguing against misguided human philosophy (Cynics) prevalent in Colosse at that time, not against the need to keep God's law:

Colossians 2:20-23New International Version (NIV)20 Since you died with Christ to the elemental spiritual forces of this world, why, as though you still belonged to the world, do you submit to its rules:21 Do not handle! Do not taste! Do not touch! 22 These rules, which have to do with things that are all destined to perish with use, are based on merely human commands and teachings.23 Such regulations indeed have an appearance of wisdom, with their self-imposed worship, their false humility and their harsh treatment of the body, but they lack any value in restraining sensual indulgence.