So you are saying Christians should honor traditions in Judaism? Isn't that the reason why there is different religions, because not everyone wants to believe the same thing?
Well there are thousands of Messianic Jews the 1st Century Christians were Jews, I don't believe that these Jews ceased practicing Judiasm even if they believed Jesus was the risen saviour and promised Messiah.
The Gentile World that became Christians have no tradition they celebrate in Judaism. You are born a Jew but you are not born a Christian.