i can't say what answer is right or wrong, since i'm a big advocate for it's always right if it's for your campaign
however, i can talk about how my gaming group handles the holy liberator within the campaign, since my character is a holy liberator and has the ability in question:
1. he is immune to all effects that are charm or compulsion, whether it be from a spell, spell-like effect, innate ability, etc.
2. this includes beneficial effects as well.
i think i could've made more of a case to my DM to allow me to lower my immunity, but, personally, i felt that the immunity was a very powerful ability, so to balance it out, i thought it made sense to be immune to "good" effects as well. plus, i thought it would lead to some interesting role-playing situations.
i can't count the times that i was glad to have that ability, especially with party members being charmed left and right.
