Bruce, I agree you're being disingenuous, unless you can tell me some practical way to distinguish a "valid defense" from an "affirmative right". Furthermore, nobody has argued that "turning off that flag" is a fair use right. They have argued that their fair use right allows them, in very common cases, to ignore the literal interpretation of the flag's name and the accompanying text in the standard. In other words, that text does not match anyone's rights. I note, further, that I frequently have other rights, beyond fair use, also not reflected in that text.
If you are arguing that some recognition of that flag is advisable, then having only the option to turn it off permanently is, equally, inadvisable. Everyone is motivated to turn it off, and then they never learn that the distributor of any given document turned it on. A reasonable implementation of the standard would display an icon indicating the flag is on, and might, on occasion, post a dialog box with a button to indicate that I know I have the right to perform the action anyhow.
Under not uncommon circumstances I really do have a right to actually turn off that flag in the file. It's neither KDE's nor Debian's business to make it hard for me to exercise that right.