Why do they not have tech to remotely disable our weapons if used against us and our allies?

Cynicism clouds the mind. Such a device would quickly be hacked, either to disable our own users or to nullify our power to disable other users.

It's like the problem the Allies faced after they cracked Enigma. You can't let people know you have something by using it.

Back in the dark time of VHS machines, certain copy-protection technologies were in place. A guy I know invented a way to defeat the copy protection. So publishers stopped using the copy protection, making the guy's invention worthless.

Ya gotta game these things out, and hating the people who make the guns that defend your freedoms can make that exercise difficult. That's why statements like "The only logical conclusion is..." are usually wrong. They mean "The only conclusion consistent with my political agenda is..." We all have political agendas, and sometimes, the conclusion consistent with our politics is also consistent with reality. But not always. In this case, I think there are technical reasons for not putting back doors in our weaponry.