Because we’re not Jews and are not bound by Jewish ritual law. No offense, really, but get this crap off of here.
Do you observe Christmas and Easter under the guise of Christian liberty? If so why do you wish to deny others that same liberty? Especially when these are the days our Lord and Savior observed?
Nowhere does the Word of God call them Jewish anything. He calls them His feasts, His appointed times and His Sabbaths. Now there is reference to Judea as in the land of Judea and the people who reside in that land in the NT, but for the sake of defining them, we must go to when the commands were given, and for that one must study that which is left of Matthew not right of Malachi.