I don't believe in the veracity of MBTI. For this reason, I don't expend much effort attempting to learn the ins and outs of the system. As such, any typing I do is based on shallow heuristics, and while I understand this, I think there are many members who have an approximately equal understanding, but do not realise.
Instead of identifying traits of INTPs, I prefer to think of it as observing traits that people claiming to be INTPs have in common.
For you, my heuristics for introversion were activated. You have a quiet voice, are not particularly assertive, seem unconfident, seem unaggressive, have eccentric interests, are into anime/broni stuff (frequent internet user hobbies), have poor verbal control, and have a demonstrated affinity for computers.
These are the things I associate with introversion. I'm guessing wonka uses similar methods, but that the methods used to determine type are more complex than this simplistic inductive reasoning.