Quite the opposite I suggest. They just don’t want to be with people of a lesser intellect, and end up bored. James

I would state that anyone who can be happy with themselves is very intelligent. It can be difficult to live solely with only one's thoughts but those who can have a benefit that others lack. They are independent and not in need of others to make this a meaningful life and that is unique. I have been this type of person my whole life. I am married 57 years have two wonderful children and four grandchildren yet I can be by myself for days at a time with no other contact and be perfectly happy. I enjoy the freedom of mind about the the things I think about sometimes silly things other times serious thoughts. It also gives me the time to determine if these thoughts should be expressed to others or retained by me and worked upon in secret ways. Company can be accomplished in other ways also. There are pets, I love my dogs and then there is nature. I find company in a water falls or a rock bed of beauty a pretty sky and by being engrossed in the nature itself. I do not need the presence of others to not feel lonely.

I don't know who said that but it's not true about intelligent people, it's true about introverts.

Introversion / extroversion is about what energizes / drains you. An extrovert is energized by socializing, an introvert is drained by it. An extrovert tends to be uncomfortable / bored with being alone, an introvert tends to be refreshed and energized by it.

Introversion has nothing inherently to do with shyness or social awkwardness, either, BTW.

Also ... being alone is not the same as being lonely. You can be alone and not be lonely; and trust me, the worst kind of loneliness is the kind you feel when surrounded by other people but feeling alienated / disconnected. Particularly, the loneliness of someone in a bad marriage.

So even if intelligence were correlated with preferring to be alone, it wouldn't have much to do with loneliness.