@Kaarme unless he is neurodivergent and hyperfocused on just the one specific skill to the detriment of everything else.
Yeah, that's what I thought he might be, earlier, but his social skills are turning out to be just fine, he's just a dumbass. In fact he doesn't even understand his own power/skill that well, which is ridiculous considering he's supposed to be a real Chuck Norris of curse artificing. Yet he apparently hasn't got a clue about the effects of his curse items when used in combat. In fact you could say he's like an idiot isekaied person, who got a "create any cursed item" cheat skill, without any particular wisdom behind the skill. So, he can create anything under the heaven, but has no concept of what exactly he's creating and is too stupid to learn, no matter how many years come and go.
If we take a real Asperger autism spectrum specimen, such a person would eventually know everything about their interest, down to the tiniest detail. However, they typically have varying degrees of trouble socialising due to many reasons. Our MC here doesn't have any such exact problems, it's his low IQ holding him back. So he may say and do weird things. Even if there's some similarity to autism spectrum, it's narrow similarity, in the end.