All the feasts pointed to Christ. We agree on that. But that is not the issue. The issue is whether we need to keep on keeping all these decayed, faded, shadowy Mosaic feasts now that the Substance, Jesus Christ, has appeared and revealed Himself as the King of Israel and the Lord of the Nations.
The NT answer is no. The apostles and elders never enjoined such behavior on anyone as a sign of proper religious conduct.
But the fruit of the Spirit is love, joy, peace, longsuffering, kindness, goodness, faithfulness, gentleness, self-control. Against such there is no law. (Gal. 5:22,23)
Nothing about law-keeping or observing feast days in there at all.
Do you live in the past unde the old covenant with the unbelieving rabbis? Or do you want to live with the new holy nation and royal priesthood as we celebrate and worship our Lord in Spirit and Truth in the simplicity of the gospel?
How is it that those who observe Christmas and Easter do so? There's not ONE hint in the bible to do so. Not even in the old testament.
Tradition and culture is how.
In the case of early Christians there was tradition, culture AND scripture. That's where they learned to observe them. Paul didn't have to instruct them. They grew up with it.
Who instructs people to observe Christmas? Where is the training? Where are the people forcing them to do it?