Those making such claims are using confusion that exists among many concerning the laws Of God.
God chose to reveal Himself to the world by MAKING the nation Israel from Abraham. NOT that small nation in the Middle East calling itself Israel. There are twelve nations that comprise the whole "house" of Israel. The Jews are only the nation of Judah. God's laws are intended for the whole earth. So are the dietary laws. We are ALL to keep the all of God's laws. It is shown in this prophecy that His laws will be enforced when Jesus returns.
Zec 14:16 And it shall come to pass, that every one that is left of all the nations which came against Jerusalem shall even go up from year to year to worship the King, the LORD of hosts, and to keep the FEAST OF TABERNACLES. (Leviticus 23, Deuteronomy 16)
Zec 14:17 And it shall be, that whoso will not come up of all the families of the earth unto Jerusalem to worship the King, the LORD of hosts, even upon them shall be no rain.
Zec 14:18 And if the family of Egypt go not up, and come not, that have no rain; there shall be the plague, wherewith the LORD will smite the heathen that come not up to keep the feast of tabernacles.
Zec 14:19 This shall be the punishment of Egypt, and the punishment of all nations that come not up to keep the feast of tabernacles.