GMAT Sentence Correction (SC) | Re: We were dismayed to learn that our neighbors were untidy,

This is a Manhattan guide question and the OA is
We were dismayed to learn that our neighbors were untidy, disagreeable, and uninterested in making new friends.

Why is to make replaced by in making here ?

Is there anything wrong in this sentence which rectifies parallelism error ?
We were dismayed to learn that our neighbors were untidy, disagreeable, and untinterested to make new friends.

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