Feast-keeping identified as "anti-christ"

This is the third consecutive post in which I am looking at the findings of the author of Feast-Keeping and the Faithful.

His third finding states his shocking conclusion to the previous two statements:

3) In short, to observe these feasts is actually “a denial of Jesus’ messiahship” (as one biblical scholar rightly noted); thus, it is a new form of being “anti-christ,” i.e., in place of (or against) Jesus Christ.

He laid the groundwork in his previous statements (see previous two posts) saying that the feasts are fulfilled by Jesus and are therefore not to be observed; that the ceremonial law, which we all know is not a biblical term, includes the holy days and that they ended, along with the rites and ceremonies, at the cross. He then extrapolates the astonishing conclusion that those who observe the days our Lord commanded us to observe are acting against Christ, and, in fact, are an anti-christ!

Christ Himself said that He came to fulfill the law, not to abolish it, yet to this day many claim that He has done just that, abolish the law by fulfilling it. Christ's definition of "fulfill" is the definition we must use.

Those who observe the feasts in this Christian era understand more of Christ's sacrifice, and more of the past, present, and future fulfillments of the prophetic aspects of God's calendar than anyone else on earth! I never thought such a thing could be said, but only by deeper studying have I understood so much of the message that God has given us, the blessing He has given us, through his annual Holy Days.

I do not understand how a person, who on the surface is kind and gracious, could make a such broad and untrue statement based on these weak foundations.