This is the kind of thinking that leads to unmaintainable AbstractFactoriesFactory classes.
Sometimes allowing repeat code is good because two functions might drift away from common functionality in the future which would require a major rework of whatever abstraction you put over them to get them under the same roof.
Even in simpler cases it can be problematic. For example, refactoring a tiny bit of repetitive code into a separate function might seem like a good idea. But, over time, things diverge and now additional parameters and branches have to be introduced to support. A small amount of repeated code is optimal.
