From what I was told, they place each one by hand. Yes, that means if there are 300 PMFs, 300 PMFs have to be added to the game, one-by-one. A better system is supposedly in the works, but... obviously not happening anytime very soon. I'm frustrated about all this too, especially since I expect a rejection due to the ambiguity of one particular rule. But I take a deep breath, tell myself it's just Elite, and try to carry on with life without stressing too much.
It's not just a matter of adding them, FD do scrutinise each of them in terms of name and lore. It's not like getting a guild HQ in an MMO, getting a PMF into the game is literally asking FD to canonise a piece of fanfiction. Trying to verify 300+ snippets of backstory for each PMF to prevent conflicts in the lore is no small task, one which doesn't even have any real in-game mechanics but instead is purely a flavour thing for players to read a little description.