Context: LaTeX is a typesetting system. When compiling a document, a lot of really in-depth debugging information is printed, which can be borderline incomprehensible to anyone but LaTeX experts. It can also be a visual hindrance when looking for important information like errors.
In my research group we could tell instantly and it would usually act as a mark against the paper (ie read this one later).
If you’re reading a lot of papers it becomes apparent.