[nimmer]

In all non-trivial codebases you have to learn how other people implemented something. It can be easy or take time depending on the how well it's written.

Macros are not different than functions: one can create readable or crazy spaghetti code in any language.

If you find a codebase full of unreadable macros it's not different than any other type of bad code: stay away from it or simplify it.

Personally, I'm yet to find a macro that makes the code less readable or more difficult to understand.