I think the purpose of the switch is the same as the write-protect notches on old floppy disks: it's not really a security measure, it's meant to prevent the owner from accidentally formatting/erasing/overwriting things.

Because engineering consumer media to be robust to a Stuxnet-level attack vector is ridiculous?

The switch as-is prevents the file system from becoming corrupt when you don't "safely remove" the device, and that's plenty enough for the average photographer.