The real reason that Christians do not celebrate feasts and holidays of the Lord is that years ago, Roman Christians sought to remove all the Jewishness from Christianity. It had nothing to do with what Jesus said because he celebrated all the feasts and holidays of his Father and we need to do the same.
Jesus observed the feasts because He was a Jewish man living in Israel in the time before the Church was born.
After the Church was born Paul wrote, “One person considers one day more sacred than another; another considers every day alike. Each of them should be fully convinced in their own mind” (Romans 14:5). And in Colossians 2:16-17 he added, “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. These are a shadow of the things that were to come; the reality, however, is found in Christ.”
I agree that the Roman church tried to distance itself from our Jewish roots, and I support your choice to observe the feasts if you believe it’s the right thing for you to do. But telling others they need to do the same is not Biblically correct.