Somehow we have binary file format parsers written in C everywhere, so the real world shows it is possible and we do have programmers capable of doing it.
Sure, we can write a binary file format parser in C. We just can't figure out how to write one that isn't buggy and lets someone infect your computer if you give it sufficiently inventive garbage.
The issue isn't whether it's possible to have parsers, but whether it's possible to have them be secure, and periodic CVEs "everywhere" suggest we don't
Somehow we also have memory safety bugs everywhere, too. So real world shows bugs in C code are possible. What even is your argument? Real men write asm?