That's right, adoption is a lot more commercial in the USA. This is how you get things like the infamous Lisa Steinberg case (child repeatedly abused and then beaten to death by her adoptive parents) where an illegal adoption went under the radar. The "Bible belt" has a problem with families who adopt a ton of children intending to train them as evangelical Christians, often turning into essentially child hoarding. Often with far more children than they can comfortably care for (this is usually on top of the family's biological children as they don't believe in birth control) or kids who come with severe disabilities that the parents cannot cope with, etc.
I think there is a lot of unfair stigma around adoption, parents insisting they only want a child who is "their blood" or believing that if the child is up for adoption they will have inherited something "wrong" from the birth parents, etc. But if you're using a surrogate, that's still genes from an extra person who isn't related to either of the parents that will be raising the child. In those instances I don't see why they'd be so opposed to adoption