There's a difference between the Conservative and Reform movement vs. the people who go to those places.
So if you want to be against Reform Judaism (the founder's daughter left the Jewish faith) then be against it. To me, Reform Judaism is just leftism with the quasi religious kumbaya veneer. But I think observant Jews and Orthodox rabbis should always try reaching out to Jews who go to these "temples."
Another thing is, it's not always easy to classify Jews as Orthodox, Conservative or Reform. For example, when I was growing up, I was friends with a girl who had an Orthodox education, and who was a pretty observant Jew, She kept kosher, observed Shabbat, the high holidays, etc. But her father bought the family a membership in the local Conservative Synagogue, and that's where she went. So for whatever reason, she and her family felt comfortable there.
As another example, the parents of a girl I used to work with were at one time members of the ultra Orthodox "Young Israel of Great Neck" Synagogue. Chaim once said that if he lived in Great Neck, he would join this Synagogue. This young woman strictly observes Shabbat, and never even worked Fridays. On the other hand, she wore her skirts above the knee, and sometimes wore sleeveless tops.
But getting back to her parents...They used to belong to Young Israel. But I was told they had problems with the board there. So they instead joined Great Neck Synagogue, which is the big main Orthodox Synagogue of Great Neck.
So I guess what I'm getting at is that it's hard to classify Jews into three groups.