I am in this discussion when this ISTP (ISTj) is bugging me and saying that socionics is a twisted and abused version of MBTI!

He says some things that I, which don't know all that much about socionics, cant really answer.

The arguments he puts forth is:

They have switched the valuation function P,J. Why? He and another guy have said earlier something like "I am a P, me and my P friends go and improvise everything! Yeah! My room is a total disaster but I know where everything is!!" Dunno about this, "we" dont see P,J as a function, right?

He critizised when I said that "Another thing about socionics is that it's easier knowing Why/how and it is mostly the relations that is interesting. I can sometimes type someone really quick with just knowing my type and recognizing the relation I had with that person"
He thinks that is not a benefit. It is like a little hobby-psychologist kit. Everything is quick and easy. It won't work on a theoretical basis, the theories are there for each one to interpret and turn into your own practice.
He also brought up the usual, "you even mix into appearance and clothing"

He won't buy the socionics theories because they have tried to make concrete and general conclusions. And in addition they've tried to "pare up" different types and then pre-decide relationships that's absurd in his eyes.

another thing you could explain to me..
The J,P differences is wheter your main functions is directed outwards or inwards.

Well, it might be a bit unstructured but I'll hope I can get some realizations and increase my knowledge further and put that socionics hater where he belong!