About the Reform, I never heard anything about treating them badly as people. Are we taught to mistreat even Goyim? Of course not. But their Temples are like churches, and it is Assur to enter them or to benefit from their facilities. Kula alma modim.
As far as dealing with them goes, I was taught not to. Austritt!!!!!! But that is not a universal Hashkofo (though maybe today it is). Of course they are Jews, but they are also dangerous people. Who cares if they know authentic Judaism or not? They are kofrim and there is no reason for interaction. (Those thinking of kiruv should realize that I am ignoring that *possible* aspect of the discussion because I have no expertise there. If you are an established, successful kiruv individual then you already have someone to turn to for this question. The rest of us can ignore kiruv.)