Part of this is because many systems are evolving, because business needs have human inputs and are not always "logical." At the edges where this human interaction happens, we expand the domain of programming to that of human psychology. There definitely are empirical claims we can make human-computer interfaces, but it begins to get a bit messy.
To be clear, I am personally interested in becoming more rigorous about empirically justifying claims I make about the code I write. But I’m also interested in code because many of the problems it attempts to solve map the very complexity of the real world. In many ways, abstraction is a properly philosophical exercise, and I think it’s impossible to separate a pure engineering discipline from this broader context.
Programming is multi-disciplinary, and I think that’s a strength.