Back when I was learning to fly, I was told the same thing, that you want wood props because the torque coming back in to the engine from a plastic prop hitting something could damage the engine or the airframe.

It might have been true many years ago. (many many many years ago), but it's BS now. There's not a modern engine out there that will take any damage before the blades shear off. Ditto the engine mounts or firewall.

If you auger in, the sudden stop you're worried about isn't the rotational one of the engine .

I've had more "sudden engine stops" flying combat with .15 and .25 engines than I care to think about. And engine or airframe damage due to something (the ground, another airplane, whatever) going in to the prop is a non-issue. And I've never seen anyone else damage an engine or plane due to the prop not breaking easily enough.

Of course, YMMV, but IMHO, the "wood props prevent damage" advice is out of date.

Oh, and wood props chop up fingers every bit as well as other materials as well. A wood prop will not break before it takes your finger off, if it comes to that. So, there's no safety advantage either.