[Nition]

> It sounds like some people...

I'd be that person. "Propagate" strongly implies a push model to me; parent-to-child reproduction like an organism.

[Talanes]

I've always read it as a purposeful lack of describing effect. A word used when you don't want to address the "how" question, just that the spread happened.

[j4yav]

Exactly, I think that’s a better way to describe it. “Propagation occurred from inside out, rather than outside in” is talking about a state changing over time, but saying nothing about how that happened.

[inopinatus]

That isn't how organisms reproduce, either.