You are right that they aren't causally connected. The OP is using the colloquial understanding of introversion. A more accurate description would be "asocial".

Psychological terms like these get confused in common-speak all the time. I am always a little thrown off when someone describes an asocial person as "antisocial", without realizing that the latter means something very different and disturbing [1].

[1] https://www.youtube.com/watch?v=BGN8bP5uJvM