I think he'll have meant what he explained it as below what you quoted.
People could play single player with all the RP they wanted, but the NPCs are going to answer a lot less than human players.
In my case it has nothing to do with RP, it has to do with exploring, gathering, buying, selling, upgrading, until I have the absolute baddest ship in the game, and then I'll go kick the shyte out of everything in my path...
And then I'll either join the Discovery 24/7 server or put the game down and play another Chris Roberts game called Privateer on my DOSBox emulator:D