Yeah, a few things. First is the NPCs, very friendly to newbies, the second is the large player base already there.
Solution for first is obvious, either nerf NPCs elsewhere (which I'd prefer, honestly) or buff NPCs in Liberty.
Second is difficult. You have to establish a trend, take say, a few friends and go to RP in say, Kusari. Over-time, slowly, people will notice you are there and dust off their un-used Kusari chars to play with you.
It's a selfless service and takes a lot of time, for not all that much personal reward, hence, few do it.