there arent "so many babies looking for a loving home" there are actually very few in the uk. Children who need adopting often come with significant problems (or are in family groups) and those will be big considerations for many people, especially people who have the means to pay for a surrogate (although surrogacy is by no means without it's problems). There are less legal hoops if the baby is staying with one of the parents too.
As this couple have not released any details (even if it is a surrogate, or what country the pregnancy is in) it's difficult to make comment on this particular situation. Of course, people are free to make comment on the general subject.