A lack of social interaction is linked to a higher risk of cardiovascular disease, dementia and more. Researchers are unpicking how the brain mediates these effects.
There's a difference between being lonely and being alone. If you're content being alone then that's not really loneliness, similarly having people around you constantly doesn't mean you can't feel a lack of connection and loneliness as well.
In other words, I agree with you, but this article seems to miss this distinction...