Sorry to break it to you, but this is the reaction of most people working on others code. It all looks like a bunch of crap held together with duct tape and string when you are the one trying to maintain it or make it do something that wasn't thought about when it was designed.
You're right that reading code is harder than writing, but I think your statement is too extreme - it implies crap code does not really exist or everything is crap. However, we all know that only 90% of everything is crap.
Personally I maintained various codebases (not written by me) and some of them were really terrible, utter mess, while some others were pretty nice to work with, even if I had to refactor sometimes. If programmers thought about code design at least for a while before writing it, and then the code is well-organized (= good separation of concerns, no global state, no copy-paste, complex parts isolated from the simple parts) - it doesn't matter that much that they didn't think of a new feature you're now adding to it.
