Pain avoidance is often disguised as disinterest, but really it's just a cost function to minimize the possibility of feeling embarrassment, awkwardness, discomfort, heated discussion, or emotional distress. Sometimes this is personality related; other times, this is a result of an aggressive, hurtful, or manipulative upbringing.
I have a friend like this and he is very hard to be friends with. He hit this point where he was stuck in an unhappy life situation (have few good friends, can't find love, etc) but vehemently opposed anything slightly uncomfortable that will move him from his unhappy cage.
What's happening subconsciously is a deep seated trauma/fear freezing him in place. For my friend, he was bullied as a kid, and his parents also were emotionally angry and abusive. He grew up with the fear that out of nowhere, a seemingly trivial sentence or action could send him into a world of confusion and hurt.
Today, meeting new people and sharing emotions is a giant minefield to him. But most people just see him as stubborn, whiny, hard to socialize with and doesn't listen to advice.
But it's hard to be his friend not because of his awkward socials but because he complains about his distress so much but doesn't do anything about it... for years. As someone who wants to solve problems and make progress, it is very frustrating to see him move so slowly.
He is very, very slow to go out from his comfort zone, even just a little bit.