It’s not completely accurate but one can make some supporting arguments toward that point if one were so inclined.
Note FORTRAN 77 (say as per ANSI X3.9-1978 document) explicitly listed only the 26 letters - A thru’ Z - as being allowed to be part of the syntactic items. The language was then de facto case sensitive in many ways, or more like it supported working with uppercase letters in code only barring instances involving character literals (usually with Hollerith) where lowercase might appear.