Because the government correctly perceives unbreakable crypto as an assault on its sovereignty.
Sovereignty is the principle that the government can do whatever it decides to do. Stuff like the 10A doesn't infringe on sovereignty because that's the government itself deciding that it shouldn't do certain things. Like if the goverment decided to, it could kick your door in, find your private diary, and read everything you've written in it. Our government has regulations moderating the use of that power, because it has decided that in most circumstances it shouldn't do that. But if the government has good reason to suspect that you're using your diary to, say, make plans for murdering people? Then the government can go right ahead and break your door down and read your diary and see if you're doing that.
(unbreakable) Crypto is different. Crypto is an infinitely high, infinitely deep wall around your house that the government can never breach, no matter how justified the government decides it is in breaching that wall. Crypto is the government sending combined might of the entire US army, navy, air force, and national guard to breach your wall, and failing. Are you within your wall engaging in acts of political speech? The government cannot stop you. Are you within your wall raping your child slaves? The government cannot stop you. Are you within your wall building a nuclear weapon that you plan to use to blow up everyone outside your wall? The government cannot stop you.
Within the cryptographic envelope, government can't govern. This isn't something the government can tolerate, because governments that can't govern aren't governments, they're just a bunch of people with opinions. So yes, the government will continue to fight these battles, because for the government these battles are an existential concern.
Sovereignty is the principle that the government can do whatever it decides to do. Stuff like the 10A doesn't infringe on sovereignty because that's the government itself deciding that it shouldn't do certain things. Like if the goverment decided to, it could kick your door in, find your private diary, and read everything you've written in it. Our government has regulations moderating the use of that power, because it has decided that in most circumstances it shouldn't do that. But if the government has good reason to suspect that you're using your diary to, say, make plans for murdering people? Then the government can go right ahead and break your door down and read your diary and see if you're doing that.
(unbreakable) Crypto is different. Crypto is an infinitely high, infinitely deep wall around your house that the government can never breach, no matter how justified the government decides it is in breaching that wall. Crypto is the government sending combined might of the entire US army, navy, air force, and national guard to breach your wall, and failing. Are you within your wall engaging in acts of political speech? The government cannot stop you. Are you within your wall raping your child slaves? The government cannot stop you. Are you within your wall building a nuclear weapon that you plan to use to blow up everyone outside your wall? The government cannot stop you.
Within the cryptographic envelope, government can't govern. This isn't something the government can tolerate, because governments that can't govern aren't governments, they're just a bunch of people with opinions. So yes, the government will continue to fight these battles, because for the government these battles are an existential concern.