They are of Jewish ethnicity, and accept Jesus as the Messiah. Why is it that one Jew can be an atheist and still be accepted as a Jew, but his brother who believes in Jesus as Messiah is not?
“They are of Jewish ethnicity, and accept Jesus as the Messiah”
No, Messiach Jews include anyone who claims to be a Jew, and claims to also believe in Jesus as the Messiah.
The Jewish ethnicity is neither here nor there, as the ethnicity doesn’t describe observance. What we have now are Jesus followers who are not of a Jewish lineage, describing themselves as being “Jews”. It’s a movement, like calling Passover “Resurrection Day”.
A basic tenet of Judaism is the belief that the Messiah has yet to arrive - it forbids a belief in Jesus as anything Messianich.
“They are of Jewish ethnicity, and accept Jesus as the Messiah. Why is it that one Jew can be an atheist and still be accepted as a Jew, but his brother who believes in Jesus as Messiah is not?”
Ditto that!