Sure, that is a potential issue with the argument. But the broader argument is that you can't make crypto go away by wishing. You can't unpublish bcrypt, libsod

Sure, that is a potential issue with the argument. But the broader argument is that you can't make crypto go away by wishing. You can't unpublish bcrypt, libsodium, OTR, Signal Protocol, and you certainly can't unpublish the maths they are based on. All you are really doing is making it inconvenient for normal, law-abiding folk to use strong crypto. A suitably motivated attacker (think ISIS, al-Qaeda etc.) could adapt to a world without crypto using some kind of steganographic approach (three poop emojis and a Miley Cyrus gif = blow the building up!). Every approach you take could be manipulated by the bad guys to their own advantage.