I don't care for drugs, or even alcohol (have lost two relaties to drunk drivers), but I understand why it's listed in the platform (as far as the criminalization of posession). Not all FRers are rabid anti-libertarians, many do in fact care about freedom and see eye-to-eye on a large part of the libertarian platform.
I have always believed that the growth and success of the libertarian message is what bothers these folks rather than anything in particular about the platform.
That might happen in Democratic circles if they too saw democrats leaving the rank and file.