I think it’s more that computers at the time didn’t all have lowercase characters. Consider that even C and C++ supported trigraph/digraph compatibility chars until something like last year (and IBM still complained…):
C is much older than Unicode, so it's not that surprising that some systems are still using https://en.wikipedia.org/wiki/ISO/IEC_646 and replacing some reserved punctuation (e.g., curly braces) with their country's accented letters.
