I think if your goal is perfect realism, sure. I don't know what it is like to be a secret agent in another country trying to persuade an asset to sell their country's secrets. And if you put me in that situation, I'd probably just end up bungling it because I have no experience with it, I don't understand the complexities. But I do have a lot of film and book analogies I can draw on for the purposes of play. And I have a lot of non-spy experience in my life that I can draw on as an approximation. I think for those of us interested in live RP at the table, this is where that is fun. But at least for me the goal isn't to achieve any kind of realism.
But then, you've seen a lot of sword fights in books and films too, haven't you? And even if you've done no combat of any sort, you've done a lot of physical activity across the course of your life.
So in the end, the difference is you're comfortable with assuming your narrative emulation of one is adequate and the other isn't. But that's the issue--its one of comfort, not something that can be demonstrated its more true with one than the other.
Still, I don't think any RPG can really capture the complex psychological processes and other details going on in a real social interaction either.
They don't capture the physical processes in combat and results either. This is incredibly obvious when you look at injury systems in RPGs, but its true of all of it. All you do is get one that's close enough for your purposes.
As I said, from where I sit it appears that two things go on, one I find more legitimate than the other:
1. People are more comfortable offloading physical processes on mechanics than they are with social (and to some degree intellectual) ones. That's fine; it can turn on how distant you feel from one or the other, and what value you get out of resolving them narratively rather than mechanically.
2. They think they have a better model for resolving social situations outside their experience than they do physical ones outside their experience. This is a massive assumption I don't think is warranted, but that some people take as a baseline that is not subject to argument.
In addition, there's a certain blindness to the fact at least some of them are okay with a problem in one area they aren't in another. As has been noted, some people are really bad at a lot of social interactions; if they're expected to be able to do so effectively in a game, they effectively can't play; they certainly can't play any character type that would be dependent on it. If you required some of the same people to actually make decisions in combat or climbing a mountain to a significant degree to participate in those, they'd have nothing but bad things to say about it. But since its not their ox being gored with the social issue, its okay there.
Also just because this free form RP, it doesn't mean you can't stop to look things up or ask someone at the table who knows about a subject that comes up. I do that a lot and don't find it disruptive. For instance if a player knows a lot about firearms, and the players go to a gunstore, I would probably ask that player for help answering questions that come up.
Watch how a fair number of GMs react to that, though. This is a case where the desire for speed in games with some people trumps damn near everything.