Then please explain to me how trees work.

Grafting is how nearly 100% of many fruit varieties are grown.

https://en.wikipedia.org/wiki/Grafting

If the tree that is being grafted into is still producing these rock hard never ripining peaches, then the tree still needs to be eradicated. Not really sure what GP's problem with the solution was.

I think they're fusing different fruit tree cuttings to a common trunk.