In both the Zimmermann and Bernstein cases the government claimed that encryption was a dangerous munition, akin to a bomb,
not akin to small arms. The second amendment doesn't generally apply to bombs. Again, extending its reach from small arms to encryption software seems highly doubtful as something you could actually get through the court system. I wasn't saying you couldn't make the argument, I was saying you would't have much luck getting a judge to accept it.
FWIW, I watched Zimmerman's case quite avidly at the time, still have a few of the
machine-readable PGP munition t-shirts squirreled away somewhere (and I'd forgotten Bernstein's name, but am familiar with his software and his cr.yp.to website).
The link results in this (as an error page on the UC Hastings site):
ERROR: This is an invalid URL. Please reenter the URL, or if you clicked a link in an email message to get here, make sure the link was not split across two lines.
Probably not what you'd intended. As I said, I paid a lot of attention to the case at the time.