However, the pronunciation of the actual body text will trigger some words to be upper case, so there's definitely a meaning under that capitalized letters.

Actually, not having the exact file may not provide a utility for you, or most of us, but searching for a file in a case sensitive manner, and getting ENOTFOUND just because it doesn't present in the way I searched is valuable from my point of view.

Also, having a case-sensitive system is simpler from technical point of view, and prone to less bugs. This is especially true after UTF-8 become ubiquitous. Searching for an exact byte stream is much more simpler than a country dependent, exceptions filled search/match algorithm.