I think chungy is right: most people get their first experience with Makefiles by trying to debug some automake monstrosity. When they write their own, they assume they have to be just as complicated (or even worse, they'll copy/paste from an autogenerated Makefile or use it as a base).

If I thought every Makefile had to be like that I'd write ./build.sh too.

I wouldn't say I'm afraid of one, but I can't read one and tell you what it does, or write one that does anything useful. Unless I'm way off the mark, it's just a programming language, one that I will eventually learn when I need it badly enough. I even snuck a manual off the freebie table at work.

It's all fun and games while your commands basically look like

    target:
        invoke-some-tool

And then, in a bigger project, you start dealing with dependencies. Exclusions. Code generation. Config-dependent builds. Dev vs stage vs prod. Sub-projects. Invocation of tools depending on other tools. Pipelines. Toolchains.

Then Makefiles quickly devolve into an incomprehensible undebuggable nightmare with arcane syntax rules and behaviours. It doesn't help that there are next to none good resources on Makefiles.