Honestly, I'm going to be a bit harsher: I think they're either:

1. A novice who doesn't know how to debug issues.

2. Totally incompetent and copying code from Stack Overflow.

I don't think it's specific to microcontrollers, either, the error from the C compiler is something that a competent programmer would be able to interpret, or at least see it as a signal to get someone more experienced in the domain to learn about.