The comma-separated-value file almost certainly comes from list-directed I/O in Fortran, which used doubling of quote characters to "escape" them. This was probably an IBM-thing since other IBM-popularised languages also do this (including SQL and COBOL). As someone else pointed out, RFC4180's own interpretation of "csv" also does this.

My guess is that they did this because parsing and encoding was simple (only a few instructions) on these systems and required no extra memory.