Teens Adopting out/Keeping Babies

Whenever a teenager posts that they are keeping their baby there is a rush of people who applaud them for making the "mature and grown up decision". This always struck me as odd because one would think the most mature decision would be the one that was best for the baby, which in most cases would be adoption. There are very few cases in which teen parents would be able to provide for their child the way an adoptive couple could with regard to emotional and financial needs, and stability. Yes not every adult is equipped to raise a child, but most teenagers are not. I do understand that it would be a very difficult decision to give child up. I just don't understand why, when someone keeps their child, that it's applauded as the "mature decision" and why adoption isn't encouraged more for those who don't want an abortion but can't practically provide for the baby.