It's not scientific yet, but there are already simple enough non-Socionics explanations for why people get along or don't get along. We might say "Because they hate each other" or "Because of their upbringing" or something like that. And you can make it as arbitrarily detailed as you'd like from there. And yes, you can eventually make that "scientific" by coming up with various theories. My hunch is that it has something to do with social identities. The reason why people can like or hate each other, is because they have certain identities. And so the answer to that is to come up with the Theory of Social Identities or something like that.
If you're going by Socionics, then you'd have to come up with ad-hoc modifications. And you say, well why is that so bad? The reason is because those additional modifications need to be further explained. You might say, "Well, it's because of Hidden Agenda..." or "It's because they're mistyped...". Ok, then how do those Hidden Agendas work? How are they mistyped? You'd need to be able to explain how exactly is it that people can be mistyped, and in what ways. And if you can't even get those basics right, then how can you even expect that Socionics "works"?