Why is one child worth more than another?
It really isn't a question of one child being worth more than another. As the parent of one child who happens to be gifted, I'm hardly going to argue that she is less important than anyone else, am I?!
The point is not that one is worth more than the other, rather that one already has a massive head start over the other. I'm not saying that gifted children never have problems, of course they do. However, they also have tremendous advantages which children at the other end of the spectrum don't have. Given that resources are limited, I would far rather invest in helping those who start at a disadvantage. It will never be possible to level the playing field, even with all of the resource in the world, but we should do whatever we can.
If children are experiencing social or emotional difficulties, or mental health problems, I think that's a separate issue from their giftedness, and needs to be treated as such. Those children absolutely need and deserve extra support, as do children with similar difficulties who don't happen to be gifted. Sadly, our mental health services are woefully under-resourced and this does need to be addressed. However, it needs to be addressed for all children (and adults!), not just those who are gifted.
Personally, I don't think giftedness itself means that a child necessarily needs special provision to be made, other than appropriate differentiation in the classroom and suitable opportunities for enrichment - which, incidentally, my dd's schools have generally managed pretty well on the whole. Where there are additional needs, this obviously does require additional support, but only a subset of gifted children will have such needs.