Your phrase "self-proclaimed gifted" is outright dismissive.
This is a natural human reaction. The reminder of the existence of people smarter than ourselves often results in narcissistic injury, it feels bad, it can hurt.
It's the reason gifted education is such a low and unpopular funding priority.
But all that does is make society poorer.
Humanity's gifted population is one of it's great resources, and we squander it. We don't protect it, and we don't value it, and we don't foster it.
The article talks about twice exceptional kids, these are kids who are gifted but often have a discrepancy or a weakness, a learning disability.
Because they are highly verbal and intelligent, they can use that to cover for their weaknesses, but they do not do well in a school setting at all.
They withdraw or they become the class clown to entertain themselves.
This often compounds over the years, like untreated ADD, and turns into depression, anxiety, substance abuse and so on.
And it's a tragedy because they have so much to offer, but we fail them, and we lose a lot of them.