What about a pacemaker? Or a car?

You have a point.

Being able to reprogram a pacemaker isn't enough!

We should require that any devices that our lives depends on, especially devices that go inside our bodies, to be open source: not just reprogrammable, but with source code available for inspection and modification.

I've been working in this industry for too long in order to trust a closed source pacemaker to be bug-free.

We can have both freedom and safety by requiring re-certification after modification. Like when you heavily physically modify a car then you can still drive it after the authorities decide it is safe.

Cars were user-reprogrammable for a long time and the sky never fell.

Requiring that the pacemaker be outside a human body in order to reprogram it seems like a very sensible solution.