> Given the nature of FSF's business you'd think they'd be on the cutting edge of digital identification and authentication.

The FSF is very careful about the legal system. Signed paper contracts are a robust legal technology. When something important happens, they don't want a judge to be distracted by unfamiliar things.

edit: they also have digital signing in a couple of different forms.

https://www.fsf.org/blogs/licensing/fsf-now-offering-paperle...