I am sure if people feel they just want a child then they would, in theory, think any child available would be fine. And if this is genuinely true then fabulous. But most of us have strengths and weaknesses and matching takes into account these strengths and tries to fit together prospective adopters who will be able to meet the needs of the children.
The reason any of this may sound like 'shopping' (it is not as no money changes place and one is not purchasing a child, even in overseas adoption where one does pay, a lot, the money is for all the services around the adoption), in the UK there is no payment. The fact is there is an element of matching.
We experienced Adoption days where you did not meet the children but instead had the chance to meet some foster carers, some social workers etc. (I can't remember what these were called!) One is literally faced with a 100 pieces of water or more, all featuring a child with their basic information and it does all feel very odd. Honestly it does.
However, when you get to the point of saying yes, I want to proceed with this child, you have basically made a decision to commit to a child for life. This decision is usually made before you meet the child and sometimes before you even see a photo of the child.
Of course, this happens naturally when you have a birth child (I have a birth child too) but I think the way things work in this country are good. The whole process revolves around the best match for that individual child.