Most adopted people I have met love their adopted parents and seem like happy people. I actually think that in some ways abuse is less common with adoption. But regardless... it takes a loving person with a warm heart to open their home.
Not on the same level, but I don't have children of my own. I do however have pets. And almost every pet has been adopted. Because why not give a loving home to something (or someone) who really needs it?
I think good, loving adoptive parents are heroes. Particularly if they are honest with their children, as you are.