If Jews are, as Herzl postulated, one people, then Diaspora Jews should very much care who the State of Israel is calling a legitimate Jew. If they are not, then of course Israeli Jews should decide anything they want. If the latter, though, should American Jews be any concerned about what happens to Israel? I'm afraid you can't have it both ways.
10 arrested at Israeli Arab protest in Ramle (Haaretz)
from the article: Netanyahu: Vote on conversion reform won't be brought to Knesset plenum