*I don't think it's reasonable to announce that you are ashamed of your country, for not taking in extra children, when you yourself are not".
Well, I think my country should have an NHS but I'm not prepared to perform heart surgery myself...
Seriously, though, I think you are assuming that the only way these children can be helped is through individuals fostering them, and given the shortage of foster carers this would put other children at risk. But there is no reason why other alternatives shouldn't be considered. It is very much the fashion to foster children in care, but other countries make more use of children's homes - not massive red-brick institutions, but groups of children living with carers in normal houses. For many older children, or children who have been severely traumatised, this kind of arrangement may be more beneficial than having to adapt to living in someone else's family.