"Let no man therefore judge you in meat, or in drink, or in respect of an holyday, or of the new moon, or of the sabbath days."
On occasion, opposers of Jehovah's Witnesses will attempt to cite Colossians 2:16 out of context in an attempt to falsely accuse Jehovah's Witnesses of unscripturally condemning others for partaking in holidays - something that Jehovah's Witnesses do not participate in. For more, see: Should We Celebrate Holidays? (bh p. 222-p. 223; Watchtower Online Library)
However, Colossians 2:16 actually refers to the God - ordained festivals and observances of the Mosaic Law, not to "holidays" in general. The context of the verse shows that Paul was saying not to judge those who chose not to celebrate those observances, not the other way around. Paul was discussing the end of the Mosaic Law - that Christians didn't need to observe it anymore. It is not dealing with pagan and/or secular holidays at all.
Furthermore, Jehovah's Witnesses fully understand and agree that it is God alone who has the right to set standards and rules for salvation. (Isaiah 33:22; Luke 12:5) Jehovah's Witnesses understand full well that it is not their prerogative to judge and condemn others. They are in complete agreement with James when he asked, “Who are you to be judging your neighbor?” (Matthew 7:1-5; Romans 14:4, 10)
For more, see:
Holidays - Links to Information