If I told a person who believed in stealing that stealing was not pleasing to God it would be a statement about what was pleasing to God, not about judging the person who believed in stealing. It is the same way about telling people God wants us to praise Him with feasts.
Jesus lived a life that had he feasts as an important part of it. Jesus did not talk about it, Jesus lived it for us. What Jesus said was that he did not change anything of the Father. When we do not do the physical part of circumcision we still obey what circumcision was to teach. When we eat pork we still obey the spiritual and earthly things that was to teach. The feasts were to praise God for His plan of redemption for us, they weren't to lead us to anything else, they WERE the praise.
To the Jews of Christ's day to say cancel all the feasts would be like telling the Christians of seventy years ago to cancel Christmas. Until the Dead Sea Scrolls were analyzed, scholars did not understand.
Actually, the feasts were given to Israel to celebrate different aspects of their history, and relationship with God, who gave them deliverance and providence. We see then that when Israel celebrated these feasts it was not with the Messiah in mind or in focus, but upon what God had done for them. So, while they indeed are a shadow of what would be fulfilled in Christ, they were not celebrated for that function (that they served as; as a shadow).
Its funny how Christmas and Easter are considered pagan holidays in origin and how we are not to celebrate them based upon origin, but hypocritically those in the HRM want to celebrate God's feasts contrary to their origin. Israel celebrated what God did for them previously, not what God was going to do through Christ (at least intellectually). So for us to super-impose our understanding of these feasts as shadows (which they were) and celebrate them with this understanding, we would be celebrating them contrary to the reason they were celebrated in the first place (as a remembrance of what God did for them previously, such as Passover).
How do we celebrate a feast that looks to the past (a specific event), and reconstruct it to celebrate a future event (that is now past for us), because it was a shadow of what was to come? In essence, we are rewriting the feasts in a way, though we understand it as a shadow, we also have to understand how and why Israel celebrated a particular feast (and in remembrance of what). How do we change their reasoning for a feast, and Christianize it (just like the pagan holidays, according to Hebrew Roots Movement), and then act as if Israel didn't celebrate, for example, Passover in remembrance of what happened in Egypt and covering the doorposts with blood, but instead celebrate the feast in knowing Christ to be the realization, the Passover Lamb?
Is this not ignoring origin and attempting to Christianize a feast, though it be a shadow? I don't dismiss the importance that such feasts foretold of the work of the Messiah, but they were celebrating and taking part of these feasts for very specific reasons. How do we remove these reasons, and replace them, without the hypocrisy of not considering origin?
While I am not equating God's feasts with pagan celebrations, I am trying to make a point that to consider origin means that we must understand why such a celebration took place. To not "Christianize" it, as is often the accusation. Does this not occur with the feasts? Celebrated originally for a specific reason but then changed, celebrated in remembrance of what Christ has done, thereby taking a shadow and still celebrating it, even though the fulfillment has come to pass? Doesn't Communion then take precedence, and instead of changing the original reason for the celebration of a feast, shouldn't we rather partake in Communion?
We acknowledge the shadow, and it pointing to Christ, but do we reinterpret the shadow so as to be able to observe it today, when that which it foretold of has "came in the flesh"? Why do we put ourselves back under the Law? To me this doesn't make sense.