Two space indentation is fairly common in C code bases.

GNU projects use a kind of hybrid indentation where child statement are indented by two spaces, but if they are compound statements the indent their interior by another two spaces:

  if (proprietary(program))
    roll_on_floor_twitching(stallman);
  else
    {
      calm_down(stallman);
      make_indent_weirdly(stallman, everyone);
    }

Google’s style guides for various "C likes" also recommend two space tabs.

"Use only spaces, and indent 2 spaces at a time." [Google C++ Style Guide, https://google.github.io/styleguide/cppguide.html]

If you've been staring at Linux kernel code for weeks, with its 8 space tabs, and the edit two-space-tab code, it will take getting used to at first. The indentation will seem small. Soon, it will expand in your mind's eye and look large.

Just because it's not uncommon doesn't mean it is not wrong, though!

And it's still easier to see in C code than something with a bunch of angly parenthesis.

The one issue with procedural is all the temporary variables and the fact that the variables themselves are intertwined with function calls. With Lisp, the whole branch is self-sufficient. It's a different reading method. Just like reading Prolog requires a different strategy.