I think there is a spectrum of difficulty in both arenas. For instance, I found writing some javascript code to toggle css around my personal website was far easier (and required less math) than sizing the pipes in the house I am designing. That said, I have also worked on much more complicated software projects that demanded more effort on my part. I assume there exist more complicated plumbing challenges as well.

It is easier, but it's physically more demanding (including being far more dangerous).

Well being physically more demanding than programming doesn't say a lot!