Yes, it does sound stupid. Only because you are comparing a Jew, which is both a religion and nation to skin color only. In addition, you compare Jews and ultimately Israel (and its law of return) to separtist liberal Blacks in America.
Your example itself makes several assumptions, by themselves an attack on Judaism and by extension the law of return in Israel. If one could only be Jewish by birth, it would be comparable to race, but since one can make a choice to be Jewish there is no comparison.
Here is your example using another example:
One is not merely Christian by merit of their birth, but by a minimal standard of behavior. This standard even applies to more secular Christians. When a Christian becomes a Islamist it is an attack on American-Christian identity. One cannot be both, as much as Muslims try to sell the idea.
Now you are being dishonest. When I rewrote your own words substituting black for Jew, I did not say anything about any "separatist liberal Blacks." Those are not my words. You added them, and they are severely off the mark.
Are you sure that you want to take such a stance against Christians who stand firmly behind Israel? That's what you are doing. Your silence on athetist Jews and erasure of Messianic Jews is anti-Christian bigotry. Point blank.