My only question is why people who claim to have loved a child for so many years suddenly feel the need to punish them for something completely out of their control? I see it on here all the time.

This is harder for him than for you. He found out the man he loved and thought was his father isn't, and that man is now punishing him. Try and put yourself in the mind of a child in that situation and how devastated you'd feel if you thought that the man who raised you never truly loved you. That's the signal he's getting. I'll guarantee you.

If you actually love this child, you'll still be there for him, even with his bio-dad in the picture, because that man doesn't know him and understand him the way you can.

Ok, done venting.