There is a huge difference between surrogacy and adoption. You have cleared it out perfectly. Surrogacy is suitable for the people who want to have a child that is biologically theirs. This is not possible for adoption. A lot of people are okay with the kids not being associated with them biologically and they are okay with it, so they go for it. In some places, surrogacy is banned. So the people of those countries stay in the dark and end up adopting against their will. Adoption is a noble thing to do of course. But one can also do what they wish to. There is nothing wrong with that.