Very simple answer: the Reform movement is not a legitimate form of Judaism. However, at least 60% of the members in these congregations are halachically Jewish. We should never give up hope that they do teshuva, however we can also NEVER work together with them in any way or show ‘unity’ to the outside world with these people chas v’sholom. There is no such thing as achdus with people who deny the Torah, even if they might be tinokei shenishba. Sure, many of their members are tinokei shenishba, but their leaders who are spreading apikorsus to the masses have a LOT to answer for if they make it up to shomayim.
