I think you’re conflating lockstep and goose step. My high school physics texts invariably used the term “lockstep” to describe a laser’s photons. Laser light doesn’t only move in a thin beam, it’s wavefronts are aligned, like twenty thousand booted feet hitting the parade ground in ,well, unison.
So I argue that the word does not currently have a negative connotation, and I’d like it not to evolve one.
Tandem is something else again.
Homeland security does have a whiff of the Fatherland to it. I object not so much to the words but the implied authoritarian wedge the idea drives into our notionally open society.