Why do the children cling to the Ghost of Christmas present?

The children have nothing and no one to cling to, they're hopeless. In the Ghost of Christmas Present they find hope.

"They are Man's,'' said the Spirit, looking down upon them. "And they cling to me, appealing from their fathers. This boy is Ignorance. This girl is Want. Beware them both, and all of their degree, but most of all beware this boy, for on his brow I see that written which is Doom, unless the writing be erased. Deny it!'' cried the Spirit, stretching out its hand towards the city. "Slander those who tell it ye! Admit it for your factious purposes, and make it worse! And bide the end!''